Category: CBSE Class 12

Here we are providing NCERT Solutions for Class 12 English Flamingo Poem 6 Aunt Jennifer’s Tigers. Students can get Class 12 English Aunt Jennifer’s Tigers NCERT Solutions, Questions and Answers designed by subject expert teachers.

Aunt Jennifer’s Tigers NCERT Solutions for Class 12 English Flamingo Poem 6

Aunt Jennifer’s Tigers NCERT Text Book Questions and Answers

Aunt Jennifer’s Tigers Think it out

Question 1.
How do “denizens” and “chivalric” add to our understanding of the tiger’s attitudes?
Answer:
Unlike their creator who sunk into the background, the tigers were described as “bright topaz denizens”. The tigers were energetic and free to “prance” or run around in the jungle, and in their creator’s imagination. The tigers were created bright, like “topaz”, and they inhabited a world that is green. The “bright topaz denizens of green” evoke a mental image of majestic tigers not bound by the whims of another being. They are in their natural environment. The tigers are conceived as inherently male, they are chivalric, hence tied to the long tradition of male authority and power. However, their “chivalric certainty” is a representation of the power envisioned by Aunt Jennifer for herself. This idea is then contrasted with Aunt Jennifer’s reality where she in turn was dominated by male superiority.

Question 2.
Why do you think Aunt Jennifer’s hands are “fluttering” through her wool in the second stanza? Why is she finding the needle so hard to pull?
Answer:
Aunt Jennifer worked with a piece of wool, stitching patterns into a tapestry. Her fingers fluttered to create the beautiful image of the tigers. She expressed her desires by creating the tigers. She found it difficult to express her feelings, repressed by the weight of marriage, gender roles, and a dominating society. “Uncle’s wedding band” is representative of the patriarchal society she lived in. The weight of the ring was not something she enjoyed as the band is described to sit ‘heavily’ on her hand and kept her from the only mode of expression she had, her needlepoint.

Question 3.
What is suggested by the image “massive weight of Uncle’s wedding band”?
Answer:
The struggle for existence in a harsh world, the deep conflicts of bondage and freedom and gender conflict is portrayed through the use of the evocative image. The genders are polarised. Aunt Jennifer was victimized by the absent Uncle, represented only by his wedding band, while he is representative of the oppression of custom and law.

Question 4.
Why is Aunt Jennifer terrified in the third stanza?
Answer:
In the last stanza, the reader is told that “the tigers in the panel she made/Will go on prancing, proud and unafraid” even after Aunt Jennifer was dead. This showed her fear. The tigers represent her spirit and how she would like to live while her hands, folded even in death, represent the reality of her life.

Question 5.
What are the ordeals Aunt Jennifer is surrounded by? Why is it significant that the poet uses the word “ringed”? What are the meanings of the word “ringed” in the poem?
Answer:
The word “ringed” has a double association. It indicates not only the ring that “sits heavily” on her hand, but the difficulties in her life that would continue to surround her.

Even in death, she is seen to conform to the patriarchal society in which she lived. The ring on her finger symbolised the weight she had to bear, dead or alive. Just as she created and controlled her needlework, society and gender roles created and controlled her.

Question 6.
Why do you think Aunt Jennifer created animals that are so different from her own character? What might the poet be suggesting, through this difference?
Answer:
Aunt Jennifer created an alternative world of freedom, one which she could not inhabit otherwise. The tigers of her creation represented her suppressed desires and her ambition. She was victimised, and stifled in marriage, by the absent figure of the Uncle, represented only by his wedding band. She escaped her reality through her creation. The poet presents an ironic image of a contrast between the common perception of animals as being brutal and of men being humane. Here, the ‘brutal’ tiger represents freedom while the ‘civilised’ man is exposed as the oppressor.

Question 7.
Interpret the symbols found in this poem.
Answer:
Adrienne Rich uses a number of similes and symbols in the poem to convey her theme. The tigers, of course, symbolise the freedom of spirit which Aunt Jennifer dreams of attaining but never achieves except in her dreams and her art. Aunt Jennifer represents of her gender rather than any one individual.

The tigers are symbolic of the true nature of the freedom that a woman’s soul represents. They also display in art the values that Aunt Jennifer must repress or displace in life: strength, assertion, fearlessness and fluidity of motion. The image of the tiger is both inspiring and destructive. And the poem’s conclusion celebrates the animal images as a kind of triumph, transcending the constraints of their maker’s life.
The word ‘ringed’ has a double connotation—indicating not only the ring that “sits heavily” on her hand, but the difficulties in her life that will continue to surround her.

Question 8.
Do you sympathise with Aunt Jennifer? What is the attitude of the poet towards Aunt Jennifer?
Answer:
As a reader, one sympathises with Aunt Jennifer. She aspired for a greater future and a greater standing for her generation. Her mind was liberated from the cloistered association with her sex, but the figure of Aunt Jennifer never got to see women standing strong and proud. In the end, Adrienne Rich showed that Aunt Jennifer represented every woman of her time. Ironically enough, she rebels using the oppressor’s own language to feel a sense of triumph. Overwhelmed by gender roles, and tom between rebellion, the need for expression, and society, Aunt Jennifer expressed her fears and desires through the exotic images of tigers, transcending her dreams and ambitions.

Aunt Jennifer’s Tigers Extra Questions and Answers

Aunt Jennifer’s Tigers Short Answer Questions

Question 1.
What are the characteristics of the tigers?
Answer:
The tigers have a striking appearance as they are described as “bright topaz”. They are energetic and prance about. They enjoy their freedom and hence run across the screen. The majestic tigers are not dictated by the whims of others. They are fearless and chivalrous. The elegant tigers are confident of themselves.

Question 2.
What do you learn about Aunt Jennifer?
Answer:
Aunt Jennifer was a weak woman with fluttering fingers. She was terrified of Uncle and found it difficult to manoeuvre the needle. Thus, implying that she was oppressed by a burdensome marriage where she was subjugated by Uncle.

Question 3.
What does Aunt Jennifer’s creation of the tigers symbolize?
Answer:
Aunt Jennifer’s creation of the tigers symbolizes her desires. Her fingers flutter to create the beautiful image of the tigers. By creating those tigers, she lets loose her inner aspirations. The wedding band sits “heavily” on her hand and keeps her from the only sense of expression she has—her needlepoint.

Question 4.
What does Aunt Jennifer’s death signify?
Answer:
In the last stanza of the poem, the poet gives us a surprisingly truthful look at the reality and the end of Aunt Jennifer and women in her position all over the world. Aunt Jennifer is a subjugated even in death; she must conform to the norms of the patriarchal society. The ring around her finger symbolizes the weight she must bear dead or alive.

Question 6.
What is the theme of the poem?
Answer:
“Aunt Jennifer’s Tigers” clearly reflects the gender struggle that women across the world are subject to. It is a feminist poem in which the poet criticizes the male-dominated world. Aunt Jennifer is left no option than to create an alternate world of freedom. Aunt Jennifer is a woman trapped by the social and cultural expectations and demands of her time.

Question 7.
Who do you think is the speaker of the poem? Why do you say so?
Answer:
The speaker of the poem is the niece; the word “Aunt” shows her relationship with the speaker. The point of view here would seem to be that of a woman, indicating that the speaker is the niece of Aunt Jennifer’s. The niece voices a woman’s struggles with expression, rebellion, and a society where power is defined as masculine. The poem deals with a woman’s representation of Aunt Jennifer’s dreams, reality and the future.

Question 8.
Interpret the following symbols found in this poem.
(a) tigers
(b) Aunt
(c) embroidery
(a) The tigers symbolize the freedom of spirit which Jennifer dreams of attaining but never achieves except in her dreams and her art.
(b) Aunt Jennifer is symbolic of women as a whole rather than one individual.
(c) Aunt Jennifer’s embroidery may exist forever as the work that she leaves behind; in life, she was nothing like the tigers in her embroidery.

Aunt Jennifer’s Tigers Value Based Question

Question 1.
How does the poet advocate gender sensitisation in the poem?
Answer:
The poem reflects the gender struggle; Adrienne Rich criticizes the male-dominated world for terrifying and oppressing women as symbolized by Aunt Jennifer, leaving her with no alternative but to create an alternate world of freedom for herself with her sewing. The embroidering of tigers on the panel, her only form of expression, underlines a woman’s struggles with expression, rebellion, and a society where power is defined as masculine. The poet depicts the pain of a woman who is living with a husband who dominates her. Her hidden, vibrant inner life is in sharp contrast to the outer image of the terrified, trapped woman.

The poem is almost a tragedy relating the plight of women trapped in an unhappy marriage. The poet makes her stance clear by using the figure of independent and fearless tigers as a telling symbol of an ideal that women like Aunt Jennifer seek to approximate. Adrienne Rich yearns for freedom and equality for all women.

Give examples from the poem of the following poetic devices.

Alliteration
“fingers fluttering”
“chivalric certainty”

Symbols
Aunt Jennifer
Tigers
Embroidery
wedding band

Here we are providing NCERT Solutions for Class 12 English Flamingo Poem 1 My Mother at Sixty-six. Students can get Class 12 English My Mother at Sixty-six NCERT Solutions, Questions and Answers designed by subject expert teachers.

Indigo NCERT Solutions for Class 12 English Flamingo Poem 1

My Mother at Sixty-six NCERT Text Book Questions and Answers

My Mother at Sixty-six Think it out 

Question 1.
What do you think is the pain and the ache that the poet feels?
Answer:
The poet was driving back from her parent’s home to Cochin, and she gazed at her mother, sleeping, beside her. The poet felt agonized at the thought of her mother growing old. The realisation that her mother was inching towards death made the poet sad as she was plagued by the thought of losing her.

Question 2.
Why are the young trees described as ‘sprinting’?
Answer:
The poet, in order to distract her mind from the painful sight, looks out of the window. The trees outside her car window rushed past her as she drove ahead. On looking out from a moving vehicle, stationary objects seem to be moving in the opposite direction. Kamala Das compared the trees to young children, with boundless energy running past her window. She uses the poetic device of personification to achieve this comparison.

Question 3.
Why has the poet used the image of the merry children “spilling out of their homes”?
Answer:
The poet saw the children rushing out of their homes. The children were young and full of life, a sad contrast to her aged mother. They represented joyousness and vitality, a contrast to the ashen visage of the poet’s ageing mother. The image of the children lends a contrast to her mood.

Question 4.
Why has the mother been compared to the “late winter’s moon”?
Answer:
The ashen and pale visage of her mother led the poet to compare her mother with that of a late winter’s moon. The winter moon that had lost its luminosity and was waning is used as a simile to compare the mother’s old and pale countenance.

Question 5.
What do the parting words of the poet and her smile signify?
Answer:
The parting words of the poet and her smile signify her pain and fear of losing her mother. She tried to put on a brave front by hiding her fear behind a smile. She tried to hide her fear from her mother as she called out, “See you soon, Amma.” The smile also might mean a forced optimism which allowed her to believe that her mother might yet live for a long time

My Mother at Sixty-six Extra Questions and Answers

My Mother at Sixty-six  Short Answer Questions

Question 1.
What are the words that convey the poet’s agony?
Answer:
Looking at her mother, drained of colour, the poet realizes that her mother had grown old and weak and had come to the end of her life. The words “familiar ache” universalizes the emotion. She talks of her mother’s frailty by comparing her to a “corpse”. She desired to dispel the pain by looking out of the car window. In the end, she was unable to speak; she could only smile.

Question 2.
Explain the contrasting situations in the poem? Why does the poet do so?
Answer:
The poem throws up various contrasts to drive home the idea and fear of the mother inching close to death. First, the mother’s lifelessness in the car is contrasted to the activity outside—the trees running, the children spilling out and the airport buzzing with activity. It contrasts with the sadness and pain in the car with the euphoric mood outside. The poet uses the contrast to highlight the dissimilarity of both the situations.

Question 3.
The mood and setting in the poem comes a full cycle. Explain.
Answer:
The poet begins with a concern and grief of the mother’s lifelessness in the car. The poet then describes the energy and jubilation outside. Once again, the mood recoils into sadness and worry, at the end of the poem, when the poet talks of her mother being pale like a late winter’s moon.

My Mother at Sixty-six Value Based Question

Question 1.
The poem deals with the subtleties of human relationships. Justify.
Answer:
The poem, “My Mother at Sixty-six” revolves around the theme of advancing age and the consequent fear of loss and separation. As the poet was on the way to airport in Cochin, she was struck by the realization that her mother was old and frail, and was overwhelmed by the fear of her parent’s impending death. She observed her mother, in her twilight years, pale and waning like the winter moon.

Like any other child, she too remembered having harboured the insecurity of losing a parent that seemed to be presently unfolding in her life. Beset with sorrow and insecurity, at the end of the poem, she bid goodbye to her aged mother at the airport. The poet undergoes the universal emotions of grief and fear of losing a parent to old age and death. Kamala Das’ eloquent and poignant verse brings out the motif of transience and passing time.

Give examples from the poem of the following poetic devices.

Simile
“… face ashen like that of a corpse
…pale as a late winter’s moon”

Personification
“.. .young trees sprinting”

Metaphor
“merry children spilling out”

Irony
“The green trees racing (inanimate) while the mother like a corpse”

Contrast
“The world replete with activity contrasted with the near lifeless mother”

Tautology
“I looked again at her, wan, pale”

Repetition
“smile and smile and smile…”

NCERT Solutions for Class 12 Chemistry Chapter 16 is the best study material for all the students. It not only prepares them for the board exams but also strengthens their concepts for competitive exams such as NEET and JEE.

The solutions are provided by subject mater experts and are accurate. The diagrammatic representations make it even easier for the students to understand. The students appearing for UP board, MP board, Gujarat board, CBSE find the NCERT Solutions beneficial while preparing for the exams.

Board	CBSE
Textbook	NCERT
Class	Class 12
Subject	Chemistry
Chapter	Chapter 16
Chapter Name	Chemistry in Every Day Life
Number of Questions Solved	37
Category	NCERT Solutions

NCERT Solutions for Class 12 Chemistry Chapter 16 Chemistry in Every Day Life

This chapter deals with the principles of chemistry in everyday life. All the products such as soaps, detergents have an organic composition. All our daily activities are controlled by chemicals. This chapter gives some interesting facts about the products we use in our daily lives and how are they controlled by the chemicals.

The students are advised to go through the NCERT solutions for Class 12 Chemstry for better understanding of the concepts provided in the chapter.

NCERT INTEXT QUESTIONS

Question 1:
Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take their doses without consultation with the doctor. Why?
Answer:
Sleeping pills contain drugs which may be tranquilizers or antidepressants. They affect the nervous system and induce sleep. However, if these doses are not properly controlled, they may create havoc. They even adversely affect the vital organs of the body. It is advisable to take these sleeping pills under the strict supervision of a doctor.

Question 2.
With refrence to which classification has the statement “ranitidine is an antacid”, been given?
Answer:
This statement refers to the classification of drugs according to pharmacological effect because any drug which will be used to neutralise the excess acid present in the stomach will be called an antacid.

Question 3.
Why do we require artificial sweetening agents?
Answer:
The commonly used sweetening agent i.e., sucrose is a carbohydrate with molecular formula C₁₂H₂₂O₁₁. Since it has high calorific value, it is not recommended to the patients, diabetics in particular which require low calorie diet. Most of the artificial sweeteners are better than sucrose but hardly provide any calories to the body. These are being used as substitutes of sugar.

Question 4.
Write chemical equations for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structural formulas of these compounds are given:
(i) (C₁₅H₃₁COO)₃C₃H₅ (Glyceryl palmitate)
(ii) (C₁₇H₃₃COO)₃ C₃H₅ (Glyceryl oleate)
Answer:

Question 5.
Label the hydrophilic and hydrophobic parts in the following molecule which is a detergent. Also identify the functional group(s) present.

Answer:

NCERT Exercise

Question 1.
Why do we need to classify the drugs in different ways?
Answer:
Drugs have been classified in different ways depending

• upon their pharmacological effect
• upon their action on a particular biochemical process
• on the basis of their chemical structure
• on the basis of molecular targets.

For example, the classification of the drugs based on pharmacological effect is useful for doctors. The classification of drugs based on molecular targets is the most useful classification for medicinal chemists. Thus, drugs are classified in different ways to serve different purposes.

Question 2.
Explain the term, target molecules or drug targets as used in medicinal chemistry.
Answer:
In medicinal chemistry, drug targets refer to the key molecules involve in certain metabolic pathways that result in specific diseases Carbohydrates, proteins, lipids, and nucleic acids are examples of drug targets.
Drugs are chemical agents designed to inhibit these target molecules by binding with the active sites of the key molecules.

Question 3.
Name the macromolecules that are chosen as drug targets.
Answer:
The different macromolecules or biomolecules which are used as drug targets are carbohydrates, proteins, enzymes, nucleic acids. Out of these, enzymes are the most significant because their deficiency leads to many disorders in the body.

Question 4.
Why should not medicines be taken without consulting doctors?
Answer:
A medicine can bind to more than one receptor site, thus a medicine may be toxic for some receptor site Further, in most cases, medicines cause harmful effects when taken in a higher dose than recommended As a result, medicines may be poisonous in such cases Hence, medicines should not be taken without consulting doctors.

Question 5.
Define the term chemotherapy. (C.B.S.E. Delhi 2008)
Answer:
The branch of chemistry which deals with the treatment of diseases using chemicals is called chemotherapy.

Question 6.
Which forces are involved in holding the drugs to the active sites of enzymes?
Answer:
These are different intermolecular forces like dipolar forces, hydrogen bonding, van der Waals’ forces etc. The receptor targets have specific roles to perform. They help in transferring message from messengers to the cell. The messengers are in fact chemical compounds which are received by the active sites of the receptor proteins that project out of the surface. In order to accommodate these, the receptors may undergo a change in shape. The receptors are held by the active sites also called binding sites. Once the message is transferred to the cells.

Question 7.
While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?
Answer:
They do not interfere with the functioning of each other because they work on different receptors in the body. Secretion of histamine causes allergy and acidity while antacid removes only acidity.

Question 8.
Low level of noradrenaline is the cause of depression. What type of drugs are needed to cure this problem ? Name two drugs (C.B.S.E. Outside Delhi 2008 Supp.)
Answer:
Low level of noradrenaline which acts as a neurotransmitter reduces the signal sending ability to the nerves and the patient suffers from depression. Antidepressants are needed to give relief from depression. These are also called tranquilizers or neurologically active drugs. The two specific drugs are iproniazid and phenelzine.

Question 9.
What is meant by the term ‘broad-spectrum antibiotic? Explain.
Answer:
Broad-spectrum antibiotics are the drugs which are effective against a large number of harmful micro-organisms causing diseases.
Chloramphenicol It is a broad-spectrum antibiotic, isolated in 1947. It is rapidly absorbed from the gastrointestinal tract and hence can be given orally. It is very effective against typhoid, dysentery, acute fever, certain form of urinary infections, meningitis and pneumonia.

Chloramphenicol is quite easy to synthesise. Therefore, most of the chloramphenicol available in the market is synthetic.

Question 10.
How do antiseptics differ from disinfectants? Give one example of each.
Answer:

Antiseptics and disinfectants are effective against micro-organisms However antiseptics are applied to the living tissues such as wounds, cuts, ulcers, and diseased skin surfaces, while disinfectants are applied to inanimate objects such as floors, drainage system, instruments, etc Disinfectants are harmful to the living tissues.

Iodine is an example of a strong antiseptic Tincture of iodine (2-3 percent of the solution of iodine in the alcohol-water mixture) is applied to wounds 1 percent solution of phenol is used as a disinfectant.

Question 11.
Why are cimetidine and ranitidine better antacids than sodium bicarbonate or magnesium or aluminium hydroxides?
Answer:
Both sodium bicarbonate and hydroxides of magnesium or aluminium are very good antacids since they neutralise the acidity in the stomach. But their prolonged use can cause the secretion of excessive acid in the stomach. This may be quite harmful and may lead to the formation of ulcers. Both cimetidine and ranitidine are better salts without any side effects.

Question 12.
Name a substance which can be used as an antiseptic as well as a disinfectant.
Answer:
Phenol can be used as an antiseptic as well as a disinfectant 0.2 percent solution of phenol is used as an antiseptic, while 1 percent of its solution is used as a disinfectant.

Question 13.
What are the main constituents of Dettol?
Answer:
The main constituents of antiseptic Dettol are chloroxylenol and terpenol.

Question 14.
What is the tincture of iodine? What is its use?
Answer:
Tincture of iodine is a 2-3 percent solution of iodine in an alcohol-water mixture It is applied to wounds as an antiseptic.

Question 15.
What are food preservatives?
Answer:
Chemical substances which are used to protect food against bacteria, yeasts and moulds are called preservatives. For example, sodium benzoate and sodium metabisulphite.

Question 16.
Why is the use of aspartame restricted to cold foods and drinks?
Answer:
Aspartame becomes unstable at cooking temperature This is the reason why its use is limited to cold foods and drinks.

Question 17.
What are artificial sweetening agents? Give two examples.
Answer:
Carbohydrates in the form of sugar (sucrose) are the traditional sweeteners and are the essential constituents of our diet. In the present lifestyle, people lack physical activities and exercise and it becomes rather difficult to burn the extra calories that are produced by the carbohydrates. Chemists have provided certain chemicals known as artificial sweeteners which provide the desired sweet taste io the food articles but hardly affect the calorie intake by the body. The most popular among the artificial sweeteners is saccharin which is nearly 550 times more sweet than the cane sugar. It is a boon for diabetic patients who don’t want to take carbohydrates (sugar) which is likely to increase the calories. It is in fact, a life saviour for these patients and is in the form of sodium or calcium salt which is water-soluble. These days, a number of other sweeteners are also available, e.g.. Aspartame, Alitame, Sucrolose etc.

(a) Aspartame: It is a very successful and commonly used artificial sweetener. As stated above, it is nearly 100 times as
sweet as cane sugar. However, it can be used in soft drinks and cold foods only since it decomposes upon heating. Chemically
aspartame is the methyl ester of dipeptide formed by the action of aspartic acid with phenylalanine.
(b) Sucrolose: The artificial sweetener as the name suggests is a trichioroderivative of sucrose. It is better, than
aspartame in the sense that it can be used in hot food at the cooking temperature, since it does not decompose on heating.
Moreover, it does not provide calories.

Question 18.
Name the sweetening agent used in the preparation of sweets for a diabetic patient.
Answer:
Artificial sweetening agents such as saccharin, alitame, and aspartame can be used in preparing sweets for diabetic patients.

Question 19.
What problem arises by using alitame as an artificial sweetener?
Answer:
Alitame is no doubt, a very potent sweetener. Its sweetening capacity is more than 2000 times as compared to ordinary cane sugar or sucrose. But sometimes, it becomes quite difficult to control the sweetness level in the food which is actually desired.

Question 20.
Why are detergents called soapless soaps?
Answer:
Soaps work in soft water, they are not effective in hard water In contrast synthetic detergents work both in soft water and hard water Therefore, synthetic detergents are better than soaps.

Question 21.
Explain the following terms with suitable examples.
(a) Cationic detergents
(b) Anionic detergents
(c) Neutral detergents.
Answer:
1. Anionic Detergents: These detergents contain anionic hydrophilic groups. These are generally made from long-chain alcohols which are reacted with concentrated sulphuric acid to form alkyl hydrogen sulphates. These are then neutralised with alkali to give water-soluble salts.
A few examples are listed below :
Sodium Alkyl Sulphates: These are the sodium salts of sulphonic acid esters of long-chain aliphatic alcohols which normally contain 10 to 15 carbon atoms. The alcohols are formed from fats and oils as a result of hydrogenolysis.

Sodium Alkyl Benzene Suiphonates: A common detergent belonging to this class is Sod – p – dodecyl benzene sulphonate. It is obtained from benzene by reacting with dodecyl chloride in the presence of anhydrous AlCl₃ acting as a catalyst.
The different steps involved are as follows :

2. Cationic Detergents: In these detergents, the hydrophilic group is of cationic nature. These are generally acetates, chlorides or bromides of quaternary ammonium CH CH CH B salts. The cationic part enclosed in the bracket contains a long hydrocarbon chain. These  detergents have germicidal qualities and are quite expensive as well, The cationic CH₃ detergents are present in hair conditioners. Cetyl trimethyl ammonium bromide

3. Non-ionic or neutral Detergent: These detergents are simply long-chain organic compounds and are esters in nature. For example, stearic acid and polyethylene glycol react to form a non-ionic detergent.

Non-ionic detergents contain polar groups and form hydrogen bonds with water. Some dishwashing liquids contain non-ionic detergents.
The field of detergents is very vast because of their immense utility. Companies engaged in their manufacture are spending huge amounts of money to bring products of better quality.

Question 22.
What are biodegradable and non-biodegradable detergents? Give an example of each. (C.B.S.E. Delhi 2008, 2009)
Answer:
Bio-degradable detergents are degraded by bacteria. In them, the hydrocarbon chain is unbranded. They do not cause water pollution and are bitter. Example: Sodium lauryl sulphate.

Non-biodegradable detergents possess highly branched hydrocarbon chain so bacteria cannot degrade them easily. They cause water pollution. Example: Sodium 4-(l, 3, 5, 7-tetramethyl-actyl) benzene sulphonate.

Question 23.
Why do soaps not work in hard water?
Answer:
Hard water contains calcium and magnesium salts. Therefore, in hard water soaps get precipitated as calcium and magnesium soaps which being insoluble stick to the clothes as gummy mass.

Question 24.
Can you use soaps and synthetic detergents to check the hardness of water?
Answer:
Soaps can be used to check hardness of water as they will form insoluble precipitates of calcium and magnesium salts on reacting with hard water. Since detergents do not form any precipitate, they cannot check hardness of water.

Question 25.
Explain the cleansing action of soaps.
Answer:
In order to understand the cleansing action of soaps let us try to analyse how the clothes become dirty. They first become oily because of the perspiration coming out of the skin and also from the organic matter dispersed in the atmosphere. Dust particles stick to oil drops and the clothes become dirty. In order to wash these, they are dipped in water and soap is applied.

In solution, it dissociates to give carboxylate ions (RCOO^–) and the cations (Na⁺). The alkyl portion which contains a long chain of hydrocarbons is a tail pointing towards the oil drops while the COO portion is the head directed towards water. This is quite evident from the figure where the solid circles (.) represent the polar groups and the wavy lines represent the alkyl portions. This formation is known as micelle and helps in forming a stable emulsion of oil and water by acting as a bridge between the two. The oil droplets along with the particles of the dirt get detached from the fibres of the clothes and pass into the emulsion. In this manner, the clothes become free from dust or dirt. The cleansing action of the soap is depicted in the Fig. 5.15.

Question 26.
If the water contains dissolved calcium bicarbonate, out of soaps and synthetic detergents, which one will you use for cleaning clothes?
Answer:
Synthetic detergents are preferred for cleaning clothes When soaps are dissolved in water containing calcium ions, these ions form insoluble salts that are of no further use, however when synthetic detergents are dissolved in water containing calcium ions, these ions form soluble salts that act as cleaning agents.

Question 27.
Label the hydrophilic and hydrophobic parts in the following compounds.
(a) CH₃(CH₂)₁₀CH₂OSO₃Na⁺
(b) CH₃(CH₂)₁₅-N⁺(CH₃)₃Br^–
(c) CH₃(CH₂)₁₆-COO(CH₂CH₂O)_nCH₂CH₂OH
Answer:

We hope the NCERT Solutions for Class 12 Chemistry Chapter 16 Chemistry in Every Day Life help you. If you have any query regarding NCERT Solutions for Class 12 Chemistry Chapter 16 Chemistry in Every Day Life, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction

These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction

Question 1.
Fill in the blanks.

1. Humans reproduce___(asexually/ sexually).
2. Humans are ___(oviparous/ viviparous/ ovoviviparous).
3. Fertilisation is___in humans (external/internal).
4. Male and female gametes are___ (diploid/haploid).
5. Zygote is___(diploid/haploid).
6. The process of release of ovum from a mature follicle is called___
7. Ovulation is induced by a hormone called ___
8. The fusion of male and female gametes is called___
9. Fertilisation takes place in ___
10. Zygote divides to form___which is implanted in uterus.
11. The structure which provides vascular connection between foetus and uterus is called ___

Solution:

1. sexually;
2. viviparous;
3. internal;
4. haploid;
5. diploid;
6. ovulation;
7. LH;
8. fertilisation;
9. ampullary-isthmic junction of Fallopian tube;
10. blastocyst;
11. placenta

Question 2.
Draw a labelled diagram of male reproductive system.
Solution:

Question 3.
Draw a labelled diagram of female reproductive system.
Solution:

Question 4.
Write two major functions each of testis and ovary.
Solution:
Testis:

1. The seminiferous tubules of the testis produce sperm.
2. The Leydig cells of testis produce hormones such as androsterone and testosterone, together called androgens.

Ovary:

1. Produce ovum
2. Produce ovarian hormones such as estradiol, estrone, and estriol collectively called estrogens.

Question 5.
Describe the structure of a seminiferous tubule
Solution:
Seminiferous tubules are located in the testicles, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa.

The lining of seminiferous tubules called germinal epithelium contains two types of cells – primary germ ceils which undergo spermatogenesis to form spermatozoa and columnar indifferent cells (derived from coelomic epithelium) which enlarge to form Sertoli cells. Sertoli cells function as nurse cells for providing nourishment to the developing spermatozoa, phagocvtise defective sperm and secrete protein hormone inhibin (which inhibits FSH secretion).

The seminiferous tubules are situated in testicular lobules. Both ends of the tubule are connected to the central region of the testis and form a network of small ductules called the rete testis.

Question 6.
What is spermatogenesis ? Briefly describe the process of spermatogenesis.
Solution:
Spermatogenesis is the process by which male spermatogonia develop into mature male gamete, spermatozoa. It starts at puberty and usually continues uninterrupted until death, although a slight decrease can be discerned in the quantity of produced sperm with increase in age. The process of spermatogenesis includes the formation of spermatogonia from germinal epithelium (primordial germ cell) through mitosis (multiplication phase). Finally they stop undergoing mitosis, grow and become primary spermatocytes (growth phase). Each spermatocyte undergoes meiosis (maturation phase). First maturation division is reductional, and produces two secondary spermatocytes. The latter divides by equational division (second maturation division) to form four haploid spermatids. Spermatids receive nourishment from the Sertoli cells to form sperms. This step is called spermiogenesis.

During this process one spermatogonium produces four sperms having half number of chromosomes.

Question 7.
Name the hormones involved in the regulation of spermatogenesis.
Solution:
The hormones involved in the regulation of spermatogenesis are:

• Gonadotropin-releasing hormone
• Luteinizing hormone (LH)
• Follicle-stimulating hormone
• Testosterone.

Question 8.
Define spermiogenesis and spermiation.
Solution:
The transformation of spermatid into sperm is called spermiogenesis. The release of sperm from the seminiferous tubules is called spermiation.

Question 9.
Draw a labelled diagram of sperm
Solution:

Question 10.
What are the major components of seminal plasma?
Solution:
Secretions of prostate gland, seminal vesicle and Cowper’s gland and , sperms together constitute semen.

Question 11.
What are the major functions of male accessory ducts and glands?
Solution:
The main functions of male accessory ducts and glands are as follows:

1. Functions of accessory ducts:

• Rete Testis: They transport sperms from seminiferous tubule to Vas efferentia.
• Vas efferentia: Transports sperms to epdidymis.
• Epididymis: Sperms are stored here. Maturation of sperms occurs.
• Vas deference: Transports sperms from the epididymis to the urethra.

2. Functions of glands:

• Prostate gland: It produces milky secretion which forms a considerable part of the semen. It makes sperm motile.
• Bulbourethral gland: Its secretion makes the penis lubricated.
• Seminal vesicle: It secretes mucus and watery alkaline fluid which provide energy to the sperm.

Question 12.
What is oogenesis? Give a brief account of oogenesis.
Solution:
Oogenesis is the production and growth of the ova (egg cell) in the ovary. It starts only after the female has attained puberty. The process is induced by FSH from the anterior pituitary. It leads to the growth of a single Graafian follicle in one of the two ovaries every month. The developing ovary is colonised by primordial germ cells prior to birth which differentiate into oogonia. These enlarge within the follicle under the influence of mitotic division to form primary oocyte containing diploid number of chromosomes. These undergo reductional division (1st meiotic division) to form a secondary oocyte and first polar body. The secondary oocyte proceeds with meiosis II but the division gets arrested until fertilisation occurs. The ‘egg’ is released at secondary oocyte stage under the effect of LH. A second polar body is extruded. The first polar body may also divide to form two polar bodies of equal sizes which do not take part in reproduction and ultimately degenerates. During oogenesis one oogonium produces one ovum and three polar bodies. Polar bodies containing small amount of cytoplasm helps to retain sufficient amount of cytoplasm in the ovum which is essential for the development of early embryo. Formation of polar bodies maintains the half number of chromosomes in the ovum.

Question 13.
Draw a labelled diagram of a section through ovary.
Solution:

Question 14.
Draw a labelled diagram of a Graafian follicle ?
Solution:

Question 15.
Give the functions of the following.

1. Corpus luteum
2. Endometrium
3. Acrosome
4. Sperm tail
5. Fimbriae

Solution:
The functions of the following:

1. Corpus luteum secretes a large amount of progesterone which is essential for the maintenance of the endometrium of the uterus.
2. Endometrium is necessary for the implantation of the fertillised ovum, for contributing towards the making of the placenta and other events of pregnancy.
3. Acrosome is filled with enzymes that help in dissolving the outer cover of the ovum and entry of sperm nucleus.
4. Sperm tail facilitates motility of the sperm essential for reaching the ovum to fertilize it.
5. Fimbriae are fingers-like projections at the mouth of fallopian tubules that help in the collection of the ovum after ovulation.

Question 16.
Identify True/False statements. Correct each false statement to make it true.

1. Androgens are produced by Sertoli cells.
2. Spermatozoa get nutrition from Sertoli cells.
3. Leydig cells are found in ovary.
4. Leydig cells synthesise androgens.
5. Oogenesis takes place in corpus luteum.
6. Menstrual cycle ceases during pregnancy.
7. Presence or absence of a hymen is not a reliable indicator of virginity Or sexual experience.

Solution:

1. False: Androgens are produced by interstitial cells or Leydig cells.
2. True
3. False: Leydig’s cells are found in the testes (in between the seminiferous tubules).
4. True
5. False: Oogenesis takes place in the ovary.
6. True
7. True

Question 17.
What is the menstrual cycle? Which hormones regulate the menstrual cycle?
Solution:
The recurring cycle of physiological changes in the uterus, ovaries and other sexual structures that occur from the beginning of one menstrual period through the beginning of the next is called menstrual cycle. The beginning of menstruation is called menarche. Hormones involved in the regulation of menstrual cycle are pituitary or ovarian hormones. These are LH, FSH, estrogen and progesterone.

Question 18.
What is parturition? Which hormones are involved in the induction of parturition?
Solution:

• The process of delivering of the fully developed fetus or baby at the end of the pregnancy period through vigorous contraction of the uterus is called parturition.
• Estrogen (amount of estrogen is more than progesterone) and oxytocin are the hormones involved in the induction of parturition.

Question 19.
In our society, women are often blamed for giving birth to daughters. Can you explain why this is not correct?
Solution:
This is not correct that women in our society are often blamed for giving birth to daughters because the sex of the baby is determined by the father, not by the mother. As we know that the chromosome pattern in the human female is XX and that in the male is XY.

Therefore, all the haploid gametes produced by the female (ova) have the sex chromosome X whereas in the male gametes (sperms) the sex chromosome could be either X or Y, hence, 50 per cent of sperms carry the X chromosome while the other 50 per cent carry the Y. After fusion of the male and female gametes the zygote would carry either XX or XY depending on whether the sperm carrying X or Y fertilised the ovum. The zygote carrying XX would develop into a female baby and XY would form a male.

Question 20.
How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?
Solution:
Each ovary develops a number of immature eggs associated with groups of other cells called follicles. Normally, in humans, only one egg is released at one time; occasionally, two or more erupt during the menstrual cycle. The egg erupts from the ovary on the 14th to 16th day of the approximately 28 day menstrual cycle. Identical twins occur when a single egg is fertilised to form one zygote (monozygotic) which then divides into two separate embryos. And if the twins were born fraternal two eggs are released. Fraternal twins (commonly known as “non-identical twins”) usually occur when two fertilised eggs are implanted in the uterine wall at the same time. The two eggs form two zygotes, and these twins are therefore also known as dizygotic as well as “binovular” twins.

Question 21.
How many eggs do you think were released by the ovary of a female dog which gave birth to 6 puppies?
Solution:
One oogonium produces one ovum and three polar bodies. The ovum is the actual female gamete. The polar bodies take no part in reproduction and hence, soon degenerate. In human beings, ovum is released from the ovary in the secondary oocyte stage. So, six ova (eggs), were released by ovary of a female dog which gave birth to 6 puppies.

We hope the NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction help you. If you have any query regarding NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction, drop a comment below and we will get back to you at the earliest.

NCERT Class 12 Chemistry solutions for Chapter 12 contains solved answers for the questions provided in the textbook. The solutions are provided stepwise in an easy language. The students find it easy to understand and can prepare well for the examination.

The students appearing for UP board, Maharashtra board, MP board, CBSE, Gujarat board, etc. can practice using NCERT Solutions. It also helps in preparing well for competitive exams such as JEE and NEET.

Board	CBSE
Textbook	NCERT
Class	Class 12
Subject	Chemistry
Chapter	Chapter 10
Chapter Name	Haloalkanes and Haloarenes
Number of Questions Solved	31
Category	NCERT Solutions

NCERT Solutions for Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes

Haloalkanes and Haloarenes is an important chapter from examination perspective. This chapter defines haloalkanes and haloarenes according to the IUPAC system of nomenclature. The reactions involved in the preparation of haloalkanes and haloarenes are also explained here. These are very important for the examination.

The chapter also explains the correlation between haloalkanes and haloarenes. NCERT Solutions for Class 12 Chapter 10 acts as a guide for the students preparing this chapter. The students can refer to these for better practice.

NCERT IN-TEXT QUESTIONS

Question 1.
Write the structures of the following compounds : (C.B.S.E. Delhi 2010)
(i) 2-Chloro-3-methylpentane
(ii) 1-Chloro-4-ethylcyclohexane
(iii) 4-tert. butyl-3-iodoheptane
(iv) 1,4-Dibromobut-2-ene
(v) 1-Bromo-4-sec butyl-2-methylbenzene. (C.B.S.E. Sample paper 2011)
Answer:

Question 2.
Why is sulphuric acid not used during the reaction of alcohols with KI?
Answer:
H₂SO₄ is an oxidising agent. It oxidises HI produced during the reaction to I₂ and thus prevents the reaction between an alcohol and HI to form alkyl iodide. To prevent this, a non¬oxidising acid like H₃PO₃ is used.

Question 3.
Write the structures of different dihalogen derivatives of propane.
Answer:
Propane (CH₃CH₂CH₃) has two primary and one secondary hydrogen atoms present. Four isomeric dihalogen derivatives are possible. Let the halogen X be Br.

Question 4.
Among the isomeric alkanes of molecular formula C₅H₁₂, identify the one which on photochemical chlorination yields
(i) A single monochloride
(ii) Three isomeric monochlorides
(iii) Four isomeric monochlorides.
Answer:
The molecular formula C₅H₁₂ represents three structural isomers which are chain isomers.

(i) The isomer is symmetrical with four primary (1°) carbon atoms and one quaternary (4°) carbon atom. Since all the hydrogen atoms are equivalent, it will yield only one monochloride upon photochlorination i.e., chlorination carried in the presence of ultra-violet light.

(ii) In the straight chain isomer pentane, there are three groups of equivalent hydrogen atoms. As a result, three isomeric monochlorides are possible.

(iii) The branched chain isomer has four types of equivalent hydrogen atoms present. It will give four isomeric monochlorides upon chlorination.

Question 5.
Draw the structures of the major monohaloproducts in each of the following reactions:

Answer:

The reaction is carried in the presence of dry acetone upon heating. It is called Finkelstein reaction. In this reaction, I^– ion being a stronger nucleophile displaces Br^– ion. NaBr formed is insoluble in dry acetone whereas Nal dissolves. This shifts the equilibrium in the forward direction.

Under the reaction conditions allylic halogenation will take place. Addition of bromine can be possible in case the reaction is carried at room temperature.

Question 6.
Arrange each set of compounds in order of increasing boiling points.
(i)Bromomethane, Bromoform, Chloromethane, Dibromomethane.
(ii)1-Chloropropane, Isopropyl chloride, 1-Chlorobutane.
Answer:
(i) Chloromethane < Bromomethane <
Dibromomethane < Bromoform
The reason is:
(a)for same alkyl group, B.Pt increases with size of halogen atom.
(b)B.Pt increases as number of halogen atoms increase.
(ii)Isopropyl chloride < 1 – Chloropropane < 1 – Chlorobutane
Reason :
(a)For same halogen, B.Pt. increases as size of alkyl group increases.
(b)B.Pt. decreases as branching increases.

Question 7.
Which alkyl halide from the following pairs would you expect to react more rapidly by S_N² mechanism ? Explain your answer.

Answer:
If the leaving group is the same in different isomers of a particular molecular formula, the reactivity of the isomers towards S_N² mechanism decreases with the increase in steric hindrance. In the light of above, the reactivity order in different cases is :

(i) CH₃CH₂CH₂CH₂Br is a primary alkyl halide (1°). It is more reactive than the other isomer which is a secondary (2°) alkyl halide because less steric hindrance is caused by primary alkyl group as compared to secondary alkyl group.
(ii)

is a secondary alkyl halide (2°). It is more reactive than the other isomer which is a tertiary alkyl halide (3°). The explanation is the same.
(iii) Here both the isomers are primary alkyl halides (1°). However, the isomer with CH₃ group at C₂ atom exerts more steric hindrance to the attacking nucleophile at C₁ atom as compared to the other isomer in which a CH₃ group is attached to C₃ atom. It is, therefore, less reactive.

Question 8.
In the following pairs of halogen compounds, which compound undergoes reaction faster ? (C.B.S.E. Delhi 2008, Outside Delhi 2010, 2013)

Answer:
The reactivity of a particular halogen compound towards S_N¹ reaction depends upon the stability of the carbocation formed as a result of ionisation. This is a slow step and is called rate determining step. The order of relative stabilities of different carbocations is in the order : tertiary > secondary > primary. In the light of this, the order of reactivity in the two cases is explained.

1. The isomer (a) is a tertiary alkyl chloride while the other isomer (b) is a secondary alkyl chloride. The isomer (a) is more reactive towards S i reaction since the tertiary carbocation formed in this case is more stable than the secondary carbocation which is likely to be formed in the other case.
2.  The isomer (a) is a secondary alkyl chloride while the other isomer (b) is primary in nature. The secondary alkyl chloride (a) is expected to react faster since the secondary carbocation formed is more stable than the primary carbocation which is likely to be formed in the other case.

Question 9.
Identify A, B, C, D, E, R and R’ in the following :

Answer:

NCERT EXERCISE

Question 1.
Name the following compounds according to IUPAC system and classify them as alkyl, allyl, benzyl (primary, secondary, tertiary) vinyl or aryl halides.
(i) (CH₃)₂CHCH(C1)CH₃ (C.B.S.E. Delhi 2013)
(ii) CH₃CH₂CH(CH₃)CH(C₂H₅)Cl
(iii) CH₃CH₂C(CH₃)₂CH₂I
(iv) CH3C(C1)(C₂H5)CH₂CH₃
(v) CH₃.C(C₂H₅)₂CH₂Br
(vi) CH₃CH=C(C1)CH₂CH(CH₃)₂
(vii) CH₂=CH-CH₂-Br
(viii) CH₃CH=CHC(Br)(CH₃)₂
(ix) m-C1CH₂C₆H₄CH₂C(CH₃)3
(x) o-BrC₆H₄CH(CH₃)CH₂CH₃
(xi) (CH₃)₃CCH₂CH(Br)C5H₅
(xii) p-ClC₆H₄CH₂CH(CH₃)₂
Answer:

Question 2.
Give the IUPAC names of the following compounds :

Answer:

Question 3.
Write the structures of the following compounds :
(i) 2-Chloro-3-methylpentane
(ii) 1-Chloro-4-ethylcyclohexane.
(iii) 2-(2-Chlorophenyi)-1-iodooctane
(iv) 4-tert. butyl -3-iodooctane
(v) 1, 4-Dibromobut-2-ene
(vi) 1-Bromo-4-sec.butyl-2-methylbenzene.
(vii) p-Bromochlorobenzene
(viii) Perfluorobenzene
Answer:

Question 4.
Which one of the following has highest dipole moment?
(a) CH₂Cl₂
(b) CHCl₃
(c) CCl₄
Answer:

CCl₄ is a symmetrical molecule. Therefore, the dipole moments of all four C-Cl bonds cancel each other. Hence its resultant dipole moment is zero.

As shown in the above figure, in CHCl₃, the resultant dipole moments of two C-Cl bonds is opposed by the resultant dipole moments of one C-H and one C-Cl bond. Since the resultant of one C-H and one C-Cl bond is smaller than the resultant of the two C-Cl bonds dipole moments, the opposition is to a small extent. As a result CHCl₃ has a small net dipole moment.

On the other hand, in case of CH₂,Cl₂ the resultant of the dipole moments of two C-Cl bonds is strengthened by the resultant of the dipole moments of two C-H bonds. As a result, CH₂Cl₂ has a higher dipole moment. Hence CH₂Cl₂ has the highest dipole moments among the three compounds.
Hence, the given compounds can be arranged in the increasing order of their dipole moments as
CCl₄ < CHCl₃ < CH₂Cl₂

Question 5.
A hydrocarbon C₅H₁₀ does not react with chlorine in dark but gives a single monobromo compound in bright sunlight. Identify the hydrocarbon.
Answer:
A hydrocarbon with the molecular formula, C₅H₁₀ belongs to the group with a general molecular form C_nH_2n. therefore, it may either be an alkene or a cycloalkane since hydrocarbon does not react with chlorine in the dark, it cannot be alkene. Further, the hydrocarbon gives a single monochloro compound, C₅H₉Cl by reacting with chlorine in might sunshine since the formed compound is monochloro one all the C-H bonds should be equivalent. Hence the compound should be a cycloalkane. Hence the compound is C₅H₁₀ (cyclopentane).

Question 6.
Write the isomers of the compound having the formula C₄H₉Br. (Haryana Board 2013)
Answer:
The compound has the following structural isomers.

2-Bromobutane has a chiral carbon and it is expected to exhibit optical isomerism.

Question 7.
Write equations for the preparation of 1-Iodobutane from :
(a) Butan-1- ol
(b) 1-Chlorobutane
(c) But-1-ene.
Answer:

Question 8.
What are ambident nucleophiles? Explain with an example.
Answer:
Nucleophiles which can attack through two different sites are called ambident nucleophiles. For example, cyanide ion exists as a hybrid of the following two structures. It can attack either

through carbon to form cyanides (or nitriles) or through nitrogen to form isocyanides (or carbyl amines). For more details, consult section 11.7.

Question 9.
Which compound in the following pairs will react faster in the Sn² reaction?
(1) CH₃Br or CH₃I
(1) (CH₃)₃CCl or CH₃Cl (C.B.S.E. 2008)
Answer:
1. In the S_N2 mechanism the reactivity of halides for the same alkyl group increase in order. This happens because as the size increases the halide ion becomes a better leaving group.
R-F << R-Cl < R – Br < R-I
Therefore, CH₃I will react faster than CH₃Br in S_N2 reaction with image 17.

2. The S_N2 mechanism involves the attack of the nucleophile at the atom bearing the leaving group. But, in the case (CH₃)₃ CCl, the attack of the nucleophile at the carbon atom is hindered by the presence of the bulky substituents on that carbon atom bearing-the leaving the group in CH₃Cl. Hence CH₃Cl reacts faster than (CH₃)₃ CCl in S_N2 reaction with

Question 10.
Predict all the alkenes that would be formed by dehydrohalogenation of following alkyl halides with sodium ethoxide in ethanol.
(i) 1-Bromo-l-metbylcyclohexane
(ii) 2-Chloro-2-methyl butane
(iii) 3-Bromo-2, 2, 3-trimethylpentane.
Answer:
(i) 1-Bromo-l-methylcyclohexane has two β-hydrogen atoms. This will give a mixture of two alkenes as a result of dehydrohalogenation. Since alkene (B) is more substituted according to SaytzefFs rule, it is more stable and will be the major product. The same rule applies to the other alkyl halides also.

(ii) The compound has two sets of β-hydrogen atoms. Therefore, two elimination products are formed. However, a more substituted alkene is formed in greater proportion as compared to a less substituted alkene.

The explanation is similar. More substituted alkene is formed in preference to less substituted alkene.

Question 11.
How will you bring about the following conversions?   (Haryana Board 2011)
(i) Ethanol to but-1-yne
(ii) Ethane to bromoethane
(iii) Propene to 1-nitropropane
(iv) Toluene to benzyl alcohol
(v) Propene to propyne
(vi) Ethanol to ethyl fluoride
(vii) Bromometbane to propanone
(viii) But-1-ene to but-2-ene
(ix) 1-Chiorobutane to n-octane
(x) Benzene to biphenyl
Answer:

Question 12.
Explain why:
(i) Dipole moment of chlorobenzene is lower than that of cyclohexyl chloride (C.B.S.E 2016)
(ii) Alkyl halides though polar, are immiscible with water.
(iii) Grignard reagents should be prepared under anhydrous conditions.
Answer:

The polarity of C- Cl bond in chlorobenzene is less than that of same bond in cyclohexyl chloride because of carbon atom involved in chlorobenzene is more electronegative (greater s-character) as compared to the carbon atom in case of cyclohexyl chloride (lesser s-character). Therefore, the dipole moment of chlorobenzene is less with respect to cyclohexyl chloride.

(ii) In water, H₂O molecules are linked to each other by intermolecular hydrogen bonding. Although alkyl halides also contain polar C – X bonds, they cannot break the hydrogen bonding in H₂0 molecules. This means that there is hardly any scope for the association between molecules of alkyl halides and water. They, therefore, exist as separate layers and are immiscible with each other. For more details, consult section 11.6.

(iii) Grignard reagents (R – Mg – X) should be prepared under anhydrous conditions because these are readily decomposed by water to form alkanes.

That is why ether used as solvent in the preparation of Grignard reagent is completely anhydrous in nature.

Question 13.
Give the uses of freon-12, D.D.T., carbon tetrachloride and iodoform?
Answer:

1. Freons are the trade names for the commercially used fluoro chloromethanes with the formula CF_xCl_y (x + y = 4). A few examples are:
   CF₄ (Freon-14), CF₃C1 (Freon-13), CF₂Cl₂ (Freon-12), CFCl₃ (Freon-11)
   Out of the various freons mentioned, Freon- 12 is the most common refrigerant. It is prepared by passing hydrogen fluoride
   through carbon tetrachionde in the presence of antimony trichioride catalyst.
   
   in addition to their use as refrigerants in place of highly toxic liquid sulphur dioxide (SO₂) and ammonia (NH₃), large amount of CFCs are also used in the manufacture of disposable foam products such as cups and plates, as aerosol propellants in spray cans and as solvents to clean freshly soldered electronic circuit boards.
2. D.D.T. is the abbreviated form of p, p’-dichlorodiphenyltrichloroethane and its actual IUPAC naine has been given above. It is
   prepared by heating chiorobenzene with chlorai (trichioroacetaldehyde) in the presence of conc. H₂S0₄
   
3. Carbon tetrachloride (CC14) is also a colourless oily liquid just like chloroform. It is completely immiscible with water but
   dissolves in organic solvents.
   Carbon tetrachloride is a very useful solvent for oils, fats, resins etc. Ills used as a cleansing agent both in industry and in home because it can easily dissolve grease and other organic matter. But it mainly finds application for the manufacture of refrigerants, propellants for aerosol cans and some pharmaceuticals.
4. lodoform is a yellow crystalline solid with a characteristic unpleasant smell. It is insoluble in water but dissolves in alcohol, ether and other organic solvents.
   lodoform can be prepared in the laboratory by treating ethyl alcohol or acetone with sodium hydroxide and iodine. The reaction is known as haloform or iodoform reaction.
5. Physiological effects: lodoform is used as an antiseptic, particularly for dressing wounds. Actually, on coming in contact with skin (organic mater) it decomposes and slowly loses iodine which accounts for the antiseptic properties of iodoform.

Question 14.
Write the structures of the major products in each of the following reactions :

Answer:

Question 15.
Explain the following reaction :    (C.B.S.E. Delhi 2009 Comptt.)

Answer:
KCN is a resonance hybrid of two contributing structures :

This shows that the cyanide ion is an ambident nucleophile and the nucleophile attack is possible either through carbon atom or nitrogen atom resulting in cyanides and isocyanides respectively. In this case, in the presence of polar solvent, KCN readily ionises to furnish ions. The nucleophile attack takes place predominantly through a carbon atom and not through nitrogen atom as C- C bond is more stable than C -N bond.

Question 16.
Arrange the compounds of each set in order of decreasing reactivity towards (S_N²) displacement:
(a) 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane
(b) 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 2-Bromo-3-methylbutane
(c) 1-Bromobutane, l-Bromo-2, 2-dimethylpropane, l-Bromo-2-methylbutane, l-Bromo-3-methylbutane. (C.B.S.E. Outside Delhi 2011)
Answer:
The reactivity of a particular haloalkane towards S_N² reaction is inversely proportional to the steric hindrance around the carbon atom involved in C – X bond. More the steric hindrance, lesser will be the reactivity. In the light of this, the decreasing order of reactivity in all the three cases is as follows :

Question 17.
Out of  C₆H₅CH₂Cl and C₆H₅CH(C1)C₆H₅ which is more easily hydrolysed by aqueous KOH?
Answer:
The compound C₆H₅CH₂Cl is a primary aralkyl halide while C₆H₅CH(Cl)C₆H₅ is secondary in nature. The hydrolysis of both these compounds with aqueous KOH (polar) is likely to proceed by S_N¹ mechanism due to the following reasons.
(a) The carbocations formed in both the cases as a result of ionisation are resonance stabilised due to the presence of phenyl groups at the a-position(s).
(b) As water is a polar solvent, it is expected to favour ionisation of the two halogen-substituted compounds leading to S_N¹ mechanism.
The carbocations that are formed as a result of ionisation in the slow steps are shown :

The ease of hydrolysis depends upon the relative stability of the carbocation/s that are formed in two cases. The secondary carbocation is more stable since the positive charge on the carbocation is delocalised on two phenyl groups that are present at the a-positions. On the other hand, there is only one phenyl group in primary carbocation available for charge delocalisation.
Thus, we may conclude that C₆H₅CHClC₆H₅ is more easily hydrolysed by aqueous KOH as compared to C₆H₅CH₂Cl.

Question 18.
p-Dichlorobenzene has higher m.p. and lower solubility than those of o-and m-isomers. Discuss.
Answer:
p-dichlorobenzene has a higher melting point than its o-isomer due to the symmetry of the p-isomer that fits in the crystal lattice better than the o- or m- isomer. Therefore, it has stronger intermolecular forces of attraction than o- and m- isomers, and thus greater energy are required to break crystal lattice to melt or dissolve the p-isomer than the corresponding o- and m- isomers. In other words, the melting point of the p-isomer is higher and its solubility is lower than corresponding m- and o- isomers.

Question 19.
How the following conversions can be carried out?
(i) Propene to propan-1-ol
(ii) Ethanol to but-1-yne
(iii) 1-Bromopropane to 2-bromopropane
(iv) Toluene to benzyl alcohol
(v) Benzene to 4-bromonitrobenzene
(vi) Benzyl alcohol to 2-phenyl ethanoic acid
(vii) Ethanol to propane nitrite
(viii) Aniline to chlorobenzene
(ix) 2-Chlorobutane to 3, 4 – dimethyl hexane
(x) 2-Methylpropene to 2-chloro-2-methylpropane
(xi) Ethyl chloride to propanoic acid
(xii) But-l-ene to n-butyl iodide
(xiii) 2-Chloropropane to propan-l-ol
(xiv) Isopropyl alcohol to iodoform
(xv) Chlorobenzene to p-nitrophenol
(xvi) 2-Bromopropane to 1-bromopropane
(xvii) Chloroethane to butane
(xviii) Benzene to diphenyl
(xix) tert-Butyl bromide to isobutyl bromide
(xx) Aniline to phenyl isocyanide.
Answer:

Question 20.
The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.
Answer:
If aqueous solution, KOH is almost completely ionized to give OH^– ions which being a strong nucleophile brings about a substitution reaction on alkyl halides to form alcohols. Further in the aqueous solution, OH^– ions are highly solvated (hydrated). This solvation reduces the basic character of OH^– ions which, therefore, fails to abstract a hydrogen from the P-carbon of the alkyl chloride to form alkenes. In contrast, an alcoholic solution of KOH contains alkoxide (RO^–) ion which being a much stronger base than OH^– ions preferentially eliminates a molecule of HCl from an alkyl chloride to form alkenes.

Question 21.
Primary alkyl halide (a) C₄H₉Br was reacted with alcoholic KOH to give compound (b). Compound (b) was reacted with HBr to give (c) which was an isomer of (a). When (a) was reacted with sodium metal, it gave a compound (d) C₈H₁₈, that was different than the compound when n-butyl bromide was reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.
Answer:
The two primary alkyl bromides are possible from the molecular formula (a) C₄H₉Br. These are:

According to the available information, the isomer (I) does not represent the correct compound because this on reacting with sodium metal (Wurtz reaction) will give n-octane. (C₈H₁₈) which is not actually formed

Question 22.
What happens when
(i) n-butyl chloride is treated with alcoholic KOH,
(ii) bromobenzene is treated with Mg in the presence of dry ether,
(iii) chlorobenzene is subjected to hydrolysis,
(iv) ethyl chloride is treated with (aq.) KOH,
(v) methyl bromide is treated with sodium in the presence of dry ether,
(vi) methyl chloride is treated with KCN?
Answer:
(i) But-l-ene is formed as the product as a result of dehydrohalogenation.

(ii) Phenyl magnesium bromide (Grignard reagent) is formed as a result of the reaction.

(iii) Chlorobenzene will not get hydrolysed on boiling with NaOH. No product will be formed.
(iv) Ethyl alcohol is formed as the product

(v) Ethane is formed as a result of Wurtz reaction

(vi) Methyl cyanide is formed.

We hope the NCERT Solutions for Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes help you. If you have any query regarding NCERT Solutions for Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and Its Applications

These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and Its Applications

Question 1.
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because
(a) bacteria are resistant to the toxin
(b) toxin is immature
(c) toxin is inactive
(d) bacteria encloses toxin in a special sac.
Solution:
(c) Toxin is inactive: In bacteria, the toxin is present in an inactive form called prototoxin. This gets converted into the active form when it enters the salivary gland of insects having an alkaline medium.

Question 2.
What are transgenic bacteria? Illustrate using any one example.
Solution:
Transgenic bacteria are one that carries a transgene or a foreign gene of interest introduced using recombinant DNA technology. e. g., bacteria carrying the genes for human insulin.

In 1983, Eli Lilly an American company prepared two DNA sequences corresponding to A and B, chains of human insulin and introduced them in plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.

Question 3.
Compare and contrast the advantages and disadvantages of the production of genetically modified crops.
Solution:
Advantages of genetically modified crops or transgenic crops are as follows :

• They are resistant to pests, herbicides and diseases.
• They help to reduce post-harvest losses.
• They enhance the nutritional value of food, e.g., a transgenic variety of rice (golden rice) is rich in vitamin A content.
• Some transgenic plants, e.g., poplar trees are used to clean up heavy metal pollution from contaminated soil.
• They are efficient in mineral usage and thus prevent early exhaustion of fertility of the soil.

Transgenic crops have several disadvantages also which are mentioned below:

• Bt toxins expressed in pollen grains of transgenic crops are harmful for useful varieties of insects, e.g., honey bees and butterflies.
• The foods produced by transgenic crops might cause toxicity and might result in allergies.
• The bacteria present in human alimentary canal can become resistant to concerned antibiotic by taking up antibiotic resistance gene present in genetically modified food and become difficult to manage.

Question 4.
What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?
Solution:
Cry proteins are a group of toxic protein which are highly poisonous to deficient types of insects. It is produced by a soil bacterium Bacillus thuringiensis. The genes controlling their formation are called cry genes eg:- Cry I Ab, Cry I Ac, Cry II Ab, The bacterium produces a protein in the crystal form of protoxin. Two cry genes have been incorporated in cotton (Bt cotton) while one has been introduced in corn (Bt corn) As a result Bt Cotton was disease resistant to bollworm and Bt corn was resistant to corn borer.

Question 5.
What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Solution:
Gene therapy is the technique of genetic engineering used to replace a faulty gene with a normal, healthy functional gene. The first clinical gene therapy was given in 1990 to a 4 years old girl with adenosine deaminase deficiency (ADA deficiency). This enzyme is very important for the immune system to function. Severe combined immunodeficiency (SCID) is caused due to a defect in the gene for the enzyme adenosine deaminase. SCID patient lacks functional T-lymphocytes and, therefore, fails to fight the infecting pathogens.

To perform gene therapy, lymphocytes are extracted from the patient’s bone marrow and a normal functional copy of human gene coding for ADA is introduced into these lymphocytes with the help of a retroviral vector. The cells so treated are reintroduced into the patient’s bone marrow. The lymphocytes produced by these cells contain functional ADA genes which reactivate the victim’s immune system. But, as these lymphocytes do not divide and are short-lived, so periodic infusion of genetically engineered lymphocytes is required. This problem can be overcome if stem cells are modified at an early embryonic stage.

Question 6.
Diagrammatically represent the experimental steps in cloning and expressing a human gene (say the gene for growth hormone) into a bacterium like E.coli?
Solution:
The given diagram represents the experimental steps in cloning and expressing a human gene for growth hormone into a bacterium E. coli.

Question 7.
Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and the chemistry of oil?
Solution:
rDNA technology is a technique of genetic engineering that involves combining DNA from two different sources to produce recombined or recombinant DNA (rDNA). Oils are composed of glycerol and fatty acids. Thus, to produce oil-free seeds genes coding for glycerol or fatty acids should be identified and nucleotide sequences complementary to the sequence of these genes should be inserted adjacent to these genes in the early cells of the endosperm. During transcription, these complementary sequences will produce anti-sense RNAs to the RNAs produced by glycerol or fatty acids gene and will silence these genes. As a result, oil-free seeds will be produced.

Since glycerol is a common component of all the oils whereas various fatty acids combine with glycerol to form oils, thus it will be easier if we silence the gene for glycerol synthesis.

Question 8.
Find out from the internet what is golden rice.
Solution:
Golden rice is a GM rice with increased vitamin A content.

Question 9.
Does our blood have proteases and nucleases?
Solution:
Proteases occur naturally in all organisms. These enzymes are involved in a multitude of physiological reactions from simple digestion of food proteins to highly-regulated cascades (e.g., the blood-clotting cascade, the complement system, apoptotic pathways, and the invertebrate prophenoloxidase activating cascade). Proteases present in blood serum (thrombin, plasmin, Hageman factor, etc.) play important role in blood clotting, as well as in lysis of the clots, and the action of the immune system. Other proteases are present in leukocytes (elastase, cathepsin G) and play several different roles in metabolic control. Nucleases, such as deoxyribonucleases and ribonucleases are found in the blood which helps in the degradation of exogenous deoxyribonucleic acid and ribonucleic acid circulating in the blood.

Question 10.
Consult the internet and find out how to make orally active protein pharmaceuticals. What is the major problem to be encountered?
Solution:
The problem is stomach enzymes and acids. Once you orally ingest a protein, the proteases in your stomach juices (trypsin, chymotrypsin, pepsin) will cleave the holy-hell out of your therapeutic protein and the acids will denature whatever’s left beyond all recognition. This is why proteins like insulin have to be injected.

We hope the NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and Its Applications help you. If you have any query regarding NCERT Solutions for Class 12 Biology Chapter 12 Biotechnology and Its Applications, drop a comment below and we will get back to you at the earliest.

Here we are providing NCERT Solutions for Class 12 English Flamingo Chapter 7 The Interview. Students can get Class 12 English The Interview NCERT Solutions, Questions and Answers designed by subject expert teachers.

The Interview NCERT Solutions for Class 12 English Flamingo Chapter 7

The Interview NCERT Text Book Questions and Answers

The Interview Think as you read 

Question 1.
What are some of the positive views on interviews?
Answer:
The positive views on interviews are that it is a medium of communication and a source of truth and information. Some even look at it as an art. These days we know about the celebrities and others through their interviews.

Question 2.
Why do most celebrity writers despise being interviewed?
Answer:
Most celebrity writers despise being interviewed because they look at interviews as an unwarranted intrusion into their lives. They feel that it diminishes them. They feel that they are wounded by interviews and lose a part of themselves. They consider interviews immoral and a crime, and an unwanted and unwelcome interruption in their personal life.

Question 3.
What is the belief in some primitive cultures about being photographed?
Answer:
Some primitive cultures consider taking a photographic portrait is like stealing the persons’s soul and diminishing him.

Question 4.
What do you understand by the expression ‘thumbprints on his windpipe’?
Answer:
Saul Bellow once described interviews as being like ‘thumbprints on his windpipe’. It means he treated interviews as a painful experience, as something that caught him by his windpipe, squeezed him and left indelible thumbprints on that. It also means that when the interviewer forces personal details from his interviewee, it becomes undesirable and cruel.

Question 5.
Who, in today’s world, is our chief source of information about personalities?
Answer:
The interviewer is the chief source of information in today’s world. Our most vivid impressions of our contemporaries are based on communication that comes from them. Thus, interviewers hold a position of power and influence.

The Interview Understanding the text

Question 1.
Do you think Umberto Eco likes being interviewed? Give reasons for your opinion.
Answer:
Umberto Eco does not think highly of interviewers who he thinks are a puzzled bunch of people. He has reasons for thinking so as they have often interpreted him as a novelist and clubbed him with Pen Clubs and writers, while he considers himself an academic scholar who attends academic conferences and writes novels on Sundays.

Question 2.
How does Eco find the time to write so much?
Answer:
Eco humorously states that there are a lot of empty spaces in his life. He calls them ‘interstices’. There are moments when one is waiting for the other. In that empty space, Eco laughingly states that he writes an article. Then he states that he is a professor who writes novels on Sundays.

Question 3.
What was distinctive about Eco’s academic writing style?
Answer:
Umberto’s writings have an ethical and philosophical element underlying them. His non-fictional writing work has a certain playful and personal quality about it. Even his writings for children deal with non-violence and peace. This style of writing makes reading his novels and essays interesting and being like the reading of most academic writings. His works are marked by an informal and narrative aspect.

Question 4.
Did Umberto Eco consider himself a novelist first or an academic scholar?
Answer:
Umberto identified himself with the academic community, a professor who attended academic conferences rather than meetings of Pen Clubs. In fact, he was quite unhappy that the people referred to him as a novelist.

Question 5.
What is the reason for the huge success of the novel, The Name of the Rose?
Answer:
The success of The Name of the Rose, though a mystery to the author himself, could possibly be because it offered a difficult reading experience to the kind of readers who do not want easy reading experiences and those who look at novels as a machine for generating interpretations. For the same reason, the sale of his novel was underestimated by his American publishers, while the readers actually enjoyed the difficult reading experience that was offered bv Umberto Eco by raising questions about truth and the order of the worid.

The Interview Extra Questions and Answers

The Interview Short Answer Questions

Question 1.
Why did Lewis Carroll have a horror of the interviewer?
Answer:
Lewis Carroll was said to have had a just horror of the interviewer. It was his horror of being lionized which made him thus repel would-be acquaintances, interviewers, and those seeking his autographs. So, he never consented to be interviewed.

Question 2.
How did Rudyard Kipling look at interviews?
Answer:
Rudyard Kipling condemned interviews. His wife writes in her diary that Rudyard Kipling told the reporters that he called being interviewed as immoral and a crime like an offence against any person. It merited punishment. It was cowardly and vile.

Question 3.
How were Rudyard Kipling and H.G. Wells critical of interviews yet they indulged in interviewing others or being themselves interviewed?
Answer:
Rudyard Kipling criticized interviews yet he interviewed Mark Twain. H.G. Wells referred to an interview in 1894 as an ordeal. Yet he was a fairly frequent interviewee. He also interviewed Joseph Stalin forty years later.

Question 4.
How are interviews, despite their drawbacks, useful?
Answer:
Despite their drawbacks, interviews are a supremely serviceable medium of communication. We get ‘ our most vivid impressions of our contemporaries through interviews. Denis Brain writes that almost everything of moment reaches us through interviews.

Question 5.
What, according to Umberto Eco, is the one thing he does through his various pieces of writing?
Answer:
According to Eco, he is always pursuing his ethical, philosophical interests which are non-violence and peace, through his academic work, his novels and even his books for children. He uses his spare moments constructively.

Question 6.
Umberto Eco tells Mukund that he has a secret. What is that?
Answer:
Umberto Eco tells Mukund that he has a secret to reveal. He tells him that there are empty spaces in the universe, in all the atoms. If they are removed, the universe will shrink to the size of a fist. He calls these empty spaces interstices and he writes in these interstices.

Question 7.
How, according to one of Eco’s professors in Italy, do scholars do in their research? How is Eco’s approach different?
Answer:
According to one of Eco’s professors in Italy, scholars made a lot of false hypotheses. They correct them and at the end they put the conclusion. But Eco told the story of his research and included his trials and errors. His professor allowed the publication of Eco’s dissertation as a book.

Question 8.
What did Umberto Eco learn at the age of 22 that he pursued in his novels?
Answer:
At the age of 22, Umberto Eco understood that scholarly books should be written the way he had done, that is, they should be written by telling the story of the research. He means to say that they should have the narrative technique. That’s why he started writing novels so late—at the age of 50.

Question 9.
How did Eco start writing novels?
Answer:
Eco states that he started writing novels by accident. One day, he had nothing to do, so he started writing. He felt that novels probably satisfied his taste for narration and he produced five novels, including the famous The Name of the Rose.

Question 10.
Did Umberto Eco consider himself a novelist first or an academic scholar? Discuss briefly.
Answer:
Umberto Eco considered himself an academic scholar, a university professor who wrote novels on Sundays. If somebody said that he was a novelist, that bothered him. He participated in academic conferences and not the meetings of Pen Clubs and writers. He identified himself with academic community.

Question 11.
What makes Eco’s The Name of the Rose a very serious novel?
Answer:
The Name of the Rose is a very serious novel. It is a detective story at one level but it also delves into metaphysics, theology and medieval history. Due to these reasons it was greatly received by the public.

Question 12.
What, according to Eco, puzzles journalists and publishers?
Answer:
According to Umberto Eco, journalists and publishers are puzzled when something unexpected happens. They believe that people like trash and do not like difficult reading experiences. But Eco’s novel The Name of the Rose, a serious work, sold between 10 and 15 million copies. This puzzled them.

Question 13.
What is the reason for the huge success of the novel, The Name of the Rose?
Answer:
The reason for the huge success of the novel, according to Eco, is a mystery. Nobody can predict it. He states that if he had written the novel ten years earlier or ten years later, it wouldn’t have been the same. So, the time component, its narrative technique, its aspects of metaphysics, theology and medieval history, made it a grand success.

Question 14.
Do you think Umberto Eco likes being interviewed? Give reasons for your opinion.
Answer:
I think Eco likes being interviewed. His answers to Mukund’s questions are straightforward, precise and to the point. They are never wavering. He even mentions his preferences about TV shows. While answering he gets humorous and laughs. Nowhere does he say anything that may give us this sort of glimpse that he does not like being interviewed.

Question 15.
Is Umberto’s informal style consciously adopted or natural?
Answer:
Umberto’s doctoral thesis was a story of his research and a sum of his experience, his trials and errors. The thesis was appreciated and published as a book. Umberto then developed on his taste for narration and this narrative aspect lends an informal touch to all his essays and novels. It makes his style alive and reading his works is not dry and boring like the reading of other academic works.

Question 16.
Why did Umberto take to writing novels?
Answer:
Umberto took to writing novels to satisfy his taste for narration. He did not have even a single novel to his credit, till the age of 50. One day having nothing to do, he started writing a novel. Moreover, he thought that novels have more readership and he could reach a larger audience.

Question 17.
What made Roiand Barthes frustrated? What did he want to do?
Answer:
Eco s friend Roland Barthes was an essayist. He was not satisfied fully with his scholarly essays. He yearned to do some creative writing. He remained frustrated that he was as essayist and not novelist. But, unfortunately he died before he could do so.

Question 18.
How did Umberto Eco become spectacularly famous?
Answer:
Umberto Eco had earned a good reputation in the field of semiotics or the study of signs. His scholarly works were staggeringly large and wide ranging. But his spectacular fame came to him with his novel The Name of the Rose which stormed the world and sold more than 10 million copies.

Question 19.
What sort of TV programmes does Eco watch after dinner and why?
Answer:
After dinner, Eco watches light television programmes like Miami Vice and Emergency Room. These programmes do not tax his mind and he feels relaxed after a hard, day’s work. But he cannot watch such programmes the whole day.

Question 20.
Bring out Umberto Eco’s humility and modesty as evident in the chapter.
Answer:
Umberto Eco takes success in his stride and talks about his achievements in all modesty. He very humbly gives credit to the people’s capability of appreciating difficult reading experiences. Regarding doing so many things, he tells that it a fallicious impression, but at the end of the day, he is doing the same thing.

The Interview Long Questions and Answers

Question 1.
The Interview as a communication genre is here to stay. Discuss with reference to the interview with Umberto Eco.
Answer:
The interview today is a communication genre that has come to stay. Its detractors—mostly celebrities— despise it as an intrusion into their lives. However, a good interview can be a source of truth, it is an excellent medium of communication and in the modern world our most vivid impressions of contemporaries are through interviews. It is through the interview that we learn about Eco’s diverse writings, his interest in the philosophy of non-violence and peace and his ability to put every spare moment to constructive use. At the interviewer’s prompting, he tells us why he writes scholarly works in an informal style and how he started writing novels. We realise that he is an academician at heart. He honestly talks of the success of his book as a mystery saying that it might •not have sold so well in another time.

Question 2.
How did Umberto Eco assess his style of writing in The Name of the Rose?
Answer:
Umberto Eco considered himself to be an academician who was happy writing novels on Sundays. Though he did not feel he was a novelist, he felt the novel fulfilled his desire for narration. In fact, he spoke of himself as a university professor who wrote novels on Sundays. The novel, according to him, enabled him to reach a larger audience. The Name of the Rose was a very serious novel. It was a detective story that delved into metaphysics, theology and medieval history’. It enjoyed a huge audience as, according to him, people did enjoy difficult reading experiences. Like him. many did not like easy experiences all the time. The novel deals with a period of medieval history and the publisher did not expect to sell so well in a state where nobody had studied Latin or seen a cathedral. He felt the timing was crucial. Perhaps its popularity would have been less, had it been written earlier or later. ‘

Question 3.
How do celebrity writers despise being interviewed as given in ‘The Interview’?
Answer:
Since its invention a little over 130 years ago, the interview has become commonplace journalism. Over the years, opinions about its functions, methods and merits vary considerably. Some say it is a source of truth and in practice, an art. Others despise it being an unwarranted intrusion into their lives. They feel it diminishes them. They equate it to taking a photographic portrait of somebody which in some primitive cultures mean ‘stealing the person’s soul.’ Some people feel wounded by interviews and lose part of themselves. They call it immoral, a crime and an assault. To some it is cowardly and vile or an ordeal.

Question 4.
How does Eco explain that he is convinced he is always doing the same thing?
Answer:
Umberto Eco explains to Mukund Padmanabhan in an interview that all the people have a lot of empty spaces. These he call ‘interstices’. He explains them through an example. He says that one is to come to him and is in an elevator and he is waiting for him. While waiting for the guest’s elevator to appear before him. he has already written an article. It means he writes in snatches of time. However, his creative ideas flow in his mind every time even when he is hosting his guest. Though he relaxes on Sundays, yet is very much busy to write novels. On other days he is busy with his academic work.

Question 5.
How does Mukund Padmanabhan comment on Eco’s academic writing style? What does Eco say about it?
Answer:
Mukund Padmanabhan states that Eco’s non-fictional writing, that is, his scholarly work has a certain playful and personal quality about it. It is a marked departure from a regular style. That regular style is invariably depersonalised and often dry and boring. To a question if he consciously adopted
an informal style, he cited the comments of one of the professors who examined and evaluated his first doctoral dissertation. The professor said that scholars learned a lot of a certain subject, then they made a lot of false hypotheses, then they corrected and put conclusions at the end. But Eco told the story of his research, including his trials and errors. At the age of 22, Eco understood that scholarly books should be written by telling the story of the research. His essays, therefore, have a narrative aspect. That is why, he wrote novels to satisfy his taste for narrative.

Question 6.
How does Mukund Padmanabhan impress you as an interviewer? Do you consider his interview with Umberto Eco a success?
Answer:
Mukund Padmanabhan’s interview with Umberto Eco tells about his capabilities as a successful interviewer. He does not encroach upon his privacy or embarrass him with personal questions. He does not come in-between the celebrity and the readers. His questions are well worded. His questions • draw out of him what his fans would like to know. The questions asked by Mukund cover all the aspects of his works and personality. Eco gives elaborated answers to all his questions. With every question, the interviewer withdraws to the background leaving the interviewee in the limelight. The whole interview does not appear to be an ordeal for the interviewee. In short it is crisp at the same time informal.

Question 7.
What are the opinions of some of the celebrities on interviews?
Answer:
Celebrities have often seen themselves as victims of interviews. In V.S. Naipaul’s opinion, interviews have left people wounded and part of them stolen. Lewis Carroll was in horror of the interviewer and he never consented to be interviewed. He often silenced all those who sought to interview him or ask for his autographs. Rudyard Kipling too held a very critical attitude towards interviews and disapproved of them after he was left almost wrecked by two reporters from Boston. According to his wife, since then he found interviews were vile, immoral and a crime. To H.G. Wells, being interviewed was an ordeal, while to Saul Bellow, interviews were like thumbprints on his windpipe, an extortion of personal details by an overbearing interviewer. They all seemed to be terrified of interviews.

Question 8.
How does the interview with Umberto Eco prove that the interview is the most commendable tool to elicit information about the interviewee?
Answer:
Mukund Padmanabhan from ‘The Hindu’ interviews Umberto Eco and proves that interview is the most commendable tool to elicit information about the interviewee.

Through his interview he reveals that Eco is a prolific writer and yet a man who is most modest about his achievements. He very humbly spells the secret of his varied and staggeringly voluminous works produced by him. When Mukund asks him about David Lodge’s remark that how one man can do all the things that Eco does’, Eco very modestly says it is a fallacious impression, in fact he has always been doing the same thing by pursuing the same philosophical ideas. He views himself as an academic, rather than a novelist. He admits that he has started writing novels by accident and writes novels on Sundays.

NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues

These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues

Question 1.
What are the various constituents of domestic sewage ? Discuss the effects of sewage discharge on a river.
Solution:
The domestic sewage contains every-thing that goes down the drain into the sewer of the house. The various constituents of domestic sewage are suspended solids, colloidal particles, pathogenic contaminants and dissolved materials. Suspended solids are sand and silt. Colloidal particles include clay, faecal matter, fine fibres of paper and cloth. Pathogenic contaminants are eggs of coliforms and enterococci. Dissolved materials includes inorganic nutrients such as nitrates, phosphates, ammonia, sodium and calcium. Effects of sewage discharge on a river :

• Water becomes unfit for bathing and drinking and also for domestic or industrial use as it becomes colored, turbid with a lot of particulate matter floating on water.
• The domestic sewage adds nitrates and phosphates into the river. These nitrates and phosphates encourage a thick bloom of blue green algae, which depletes the oxygen content of the water during night. This suffocates the fish and other aquatic life. Consequently river become highly polluted.

Question 2.
List all the wastes that you generate, at home, school, or during your trips to other places. Could you very easily reduce the generation of these wastes? Which would be difficult or rather impossible to reduce?
Solution:
Wastes generated at home include plastic bags, paper napkins, toiletries, kitchen wastes (such as peelings of vegetables and fruits, tea leaves), domestic sewage, glass, etc.

Wastes generated at school include waste paper, plastics, vegetable and fruit peels, food wrapping, sewage, etc. Wastes generated at trips or picnics include plastic, paper, vegetable and fruit peels, disposable cups, plates, spoons etc.

Yes, wastes can be easily reduced by the judicious use of the above materials. Wastage of paper can be minimized by writing on both sides of the paper and by using recycled paper.

Plastic and glass waste can also be reduced by recycling and re-using. Also, substituting plastic bags with biodegradable jute bags can reduce wastes generated at home, school or during trips. Domestic sewage can be reduced by optimizing the use of water while bathing, cooking, and other household activities.

Non-biodegradable wastes such as plastic, metal, broken glass, etc. are difficult to decompose because microorganisms do not have the ability to decompose them.

Question 3.
Discuss the causes and effects of global warming. What measures need to be taken to control global warming?
Solution:

• Global warming is a rise in the mean temperature of the lower atmosphere and the earth’s surface. Causes – increase in the quantity of radioactively active greenhouse gases CO₂, CH₄, N₂O, CFCs. They allow heat waves to reach the surface and prevent their escape.
• They are produced by combustion of fossil fuels, biomass [CO₂]; burning of nitrogen-rich fuels [N₂O]; paddy fields, fermentation in cattle and wetlands [CH₄]; refrigerators, aerosols, drying, cleaning [CFCs].
• Effects: Heating of earth surface [mean temperature is increased] Climatic changes e.g.: El Nino effect.
• Increased melting of polar ice caps and Himalayan snowcaps. Increased sea levels and coastal areas will submerge.
• Measures – Decreased use of fossil fuels, improve the efficiency of energy usage, Reduce deforestation, plant trees Control of man-made sources of greenhouse gases like vehicles, aerosol sprays.

Question 4.
Match the items given in Column A and B
column A                                       Column B
(a) Catalytic converter               (i) Particulate matter
(b) Electrostatic precipitator    (ii) Carbon monoxide and nitrogen oxides
(c) Earmuffs                               (iii) High noise level
(d) Landfills                               (iv) Solid wastes
Solution:
(a) – (ii); (b) – (i); (c) – (iii); (d) – (iv).

Question 5.
Write critical notes on the following :
(a) Eutrophication
(b) Biological magnification
(c) Groundwater depletion and ways for its replenishment
Solution:
(a) Eutrophication: The natural aging process of lakes by nutrient enrichment of their water. In young lake water is cold and clear and supports only little life. With time, streams introduce nutrients into lake which increases lakes’ fertility and encourages aquatic growth. Over centuries silts and organic debris pile up, and lake becomes shallow and warmer. It supports plants and later gets converted into land. Lakes span depends on the climate, size of lake.

(b) Biological magnification: Industrial wastes released into water contain toxic substances, such as arsenic, cadmium, lead, zinc, copper, mercury, and cyanides, besides some salts, acids, and alkalies. All these materials can prove harmful for our health.

They may reach the human body directly with contaminated food or indirectly by way of plants and other animals. The concentration of the toxic materials increases at each trophic level of a food chain. This is called biological magnification. River water may have a very low concentration of DDT, but the carnivorous fish in that river may contain a high concentration of DDT and become unfit for eating by man. Mercury discharged into rivers and lakes is changed by bacteria to the neurotoxic form called methyl mercury. The latter is highly poisonous and may be directly absorbed by fish.

(c) Groundwater depletion and ways for its replenishment: Groundwater depletion is defined as long-term water-level decline caused by sustained groundwater pumping. The volume of ground water in storage is decreasing in many areas of the world in response to pumping. Some of the negative effects of groundwater depletion include increased pumping costs, deterioration of water quality, reduction of water in streams and lakes.
Some ways for water replenishment are:

• Reduction in consumption: Sprinkler and subsurface irrigation techniques reduce the amount of water used in irrigation.
• Rain water harvesting: Rain water collected over roofs is allowed to pass into the ground through deep water pipes.

Question 6.
Why does the ozone hole form over Antarctica? How will enhanced ultraviolet radiation affect us?
Solution:
Ozone hole forms over Antarctica where no one lives and no pollution is present but not over Newyork, Bangalore etc., (polluted cities). It is because CFCs and ozone-depleting substances (ODS) released worldwide accumulates in the stratosphere and drifts towards, Antarctica in winters (July – August) when temperatures is -’85° C in Antarctica.

In winters polar ice clouds are formed over Antarctica. It provides a catalytic surface for (CFCs and other ODS to release CL and other free radicals that breakdown ozone layer forming an ozone hole during spring in presence of sunlight. In summer, the ozone hole disappears due to mixing of air worldwide.

Ozone holes allow UV radiations (UV_A & UV_B) to reach earth’s surface. Which was earlier reflected by the ozone layer. UV_B damages DNA, skin cells and causes mutations and skin cancers respectively. UV_B even causes corneal damage (Snow Blindness).

Question 7.
Discuss the role of women and communities in protection and conservation of forests.
Solution:
Forest Conservation and Management:
It is time to think deeply and act seriously in order to protect this vital natural resource. Some of the measures of conservation are

1. Social forestry programme: It was started in 1976 and involves the affor­estation on public and common lands for fuel, fodder, timber for agricul­tural equipment and fruits. These are mainly meant for rural people.
2. Agroforestry programme: It involves the multiple use of same land for agriculture, forestry and animal husbandary. Taungya System and Jhum are examples.
   • Taungya System: It involves growing agricultural crops between planted trees.
   • Jhum (Slash and burn agriculture): It involves felling and burning of forests, followed by the cultivation of crops for a few years. Later the cultivation is abandoned for the growth of forests. It is a traditional agroforestry system.
3. Urban forestry programme: It involves afforestation in urban land ar­eas e.g. along the roads, big parks, big compounds etc. with ornamental and fruit trees.
4. Commercial forestry: It involves planting of fast-growing trees on avail­able land to fulfill commercial demand.
5. Conservation forestry: It involves protection of degraded forest to allow recoupment of their flora and fauna.

Reforestation: It is the process of restoring a forest that once existed, but was removed at some point of time in the past. Reforestation may occur naturally in a deforested area. The above-said methods speed up the refor­estation programme.

Question 8.
What measures, as an individual, you would take to reduce environmental pollution?
Solution:
To reduce environmental pollution, we should change our habits and lifestyle so as to reduce the use of disposable materials. We should use preferably those items which can easily be recycled and also minimise the use of fossil fuels. We should also take measures to improve the quality of air by using CNG gases wherever possible instead of using diesel or petrol. We should also use the catalytic converter in our vehicles.

Question 9.
Discuss briefly the following:
(a) Radioactive wastes
(b) Defunct ships and e-wastes
(c) Municipal solid wastes
Solution:
a. Radioactive waste materials are released from thermonuclear explosions. Radioactive isotopes, such as radium-226, thorium- 232, potassium-40, uranium-235, carbon-14, etc. are spread all over the world and contaminate air, soil, water, vegetation and animals.

b. Irrepairble electronic goods and computers are called electronic wastes (e-waste).
Ships that are no longer in use or that are to be dismantled are called defunct ships. Asbestos, Polychlorinated Biphenyl (PCB) produced during dismantling defunct ship cause serious health hazards especially cancer.

c. Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals, etc., that are collected and disposed of by the municipality.

Question 10.
What initiatives were taken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi?
Solution:
Under the direction of Supreme Court of India, the State Government of Delhi took the following measures to improve the quality of air:

• Switching over the entire fleet of public transport buses from diesel to CNG (Compressed Natural Gas) by the end of 2002.
• Phasing out of old vehicles.
• Use of unleaded petrol.
• Use of low sulphur petrol and diesel.
• Use of catalytic converters in vehicles.
• Application of Euro II norms for vehicles.

Because of above mentioned measures adopted by the Government the air quality of Delhi has improved with a substantial fall in S0₂, CO, No_x level between 1997-2005.

Question 11.
Discuss in brief the following:
(a) Green house gases
(b) Catalytic converter
(c) Ultraviolet B
Solution:
(a) Green house gases: The gases which are transparent to solar radiation but retain and partially reflect back long wave heat radiations are called greenhouse gases. Green house gases are essential for keeping the earth warm and hospitable. They are also called radiatively active gases. They prevent a substantial part of long wave radiations emitted by earth to escape into space. Rather green house gases radiate a part of this energy back to the earth. The phenomenon is called greenhouse flux. Because of greenhouse flux, the mean annual temperature of the earth is 15°C. In its absence, it will fall to – 18°C.

However, recently the concentration of greenhouse gases has started rising to result in an enhanced greenhouse effect that is resulting in increasing the mean global temperature. It is called global warming. A regular assessment of the abundance of greenhouse gases and their impact on the global environment is being made by IPCC (Intergovernmental Panel on Climate Change). The various green house gases are CO₂ (warming effect 60%), CH₄ (effect 20%) , chlorofluorocarbons or CFCs (14%) andT nitrous oxide (N₂O, 6%). Others of minor significance are water vapors and ozone.

(b) Catalytic converter: Catalytic converters are devices that are fitted into automobiles for reducing the emission of gases. These have expensive metals (platinum – palladium, and rhodium) as catalysts. As the exhaust passes through the catalytic converters, unburnt hydrocarbons are converted into CO₂ and H₂O and carbon monoxide and nitric oxide are changed to CO₂ and N₂ respectively. Vehicles fitted with catalytic converters should be run on unleaded petrol as leaded petrol would inactivate the catalyst in the converters.

(c) Ultraviolet B – UV-B having 280-320nm wavelength. Their harmful radiations penetrate through the ozone hole to strike the earth. On earth, these can affect human beings and other animals by causing :

• Skin cancer
• Blindness and increased incidence of cataract in eyes, and
• Malfunctioning of the immune system.
• Higher number of mutations.

We hope the NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues help you. If you have any query regarding NCERT Solutions for Class 12 Biology Chapter 16 Environmental Issues, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 History Chapter 8 Peasants, Zamindars and the State Agrarian Society and the Mughal Empire are part of NCERT Solutions for Class 12 History. Here we have given NCERT Solutions for Class 12 History Chapter 8 Peasants, Zamindars and the State Agrarian Society and the Mughal Empire.

Board	CBSE
Textbook	NCERT
Class	Class 12
Subject	History
Chapter	Chapter 8
Chapter Name	Peasants, Zamindars and the State Agrarian Society and the Mughal Empire
Number of Questions Solved	9
Category	NCERT Solutions

NCERT Solutions for Class 12 History Chapter 8 Peasants, Zamindars and the State Agrarian Society and the Mughal Empire

Question l.
What are the problems in using the Ain as a source for reconstructing agrarian history ? How do historians deal with this situation ?
Solution :
(a) Problems : The Ain was revised five times by the author so that it might become authentic. In all the quantitative sections, all numeric data were reproduced in words so as to minimise the chances of errors. But in spite this there are following problems in using Ain as a source for reconstructing agrarian history :

1. Numerous errors in totalling have been detected. These are ascribed to simple slips of arithmetic or of transcription by Abul Fazl’s assistants.
2. Another problem is about the somewhat skewed nature of the quantitative data. Data were not collected uniformly from all provinces. For example, detailed information about caste composition of the zamindars was collected from many subas. However, such information is not available for Bengal and Orissa.
3. Prices and wages that have been documented in the Ain pertains to areas in or around the imperial capital of Agra. It has, therefore, limited relevance for the rest of the country.
4. Ain was to present a vision of Akbar’s empire where social harmony was provided by a strong ruling class. There was no place for a successful revolt against the Mughal state. Thus, whatever we learn about the peasants from the Ain remains a view from the top.

(b)

1. The historians deal with the above problems by supplementing the descriptions contained in sources emanating from regions away from the Mughal capital, e.g., revenue records from Gujarat, Maharashtra and Rajasthan from the seventeenth and eighteenth centuries.
2. The extensive records of the East India Company too provide useful descriptions of agrarian relations in eastern India. These sources describe the instances of conflicts between peasants, zamindars and the state. Thus, they provide an insight into peasants’ perception of and their expectations of fairness from the state.

Question 2.
To what extent is it possible to characterise agricultural production in the sixteenth- seventeeth centuries as subsistence agriculture? Give reasons for your answer.
Solution :
(a) During Mughal, India was basically an agricultural country. In the Mughal state of India a different varieties of crops were produced. In Bengal two varieties of rices were produced. But the focus on the cultivation of basic crops does not mean that only subsistence agriculture existed in medieval India.
(b) The Mughal state encouraged peasants to cultivate varieties of crops which brought in revenue especially cotton and sugarcane.
(c) Cotton was mainly grown in vast area which was spread over central India and the deccan plateau, whereas in Bengal sugarcane was mainly produced.
(d) Many varieties of cash crops such as oilseeds including mustard and lentils.
(e) An average peasant of that time grew both commercial and subsistence crops.

Question 3.
Describe the role played by women in agricultural production.
Solution :
The role played by women in agricultural production was as mentioned below :

• Men and women worked shoulder to shoulder in the fields.
• Men tilled and ploughed, while women sowed, weeded, threshed and winnowed the harvest.
• During the medieval period, with the growth of nucleated villages and expansion in individuated peasant farming, the basis of production was the labour and resources of the entire household.
• Inspite of above, there were biases related to women’s biological functions. For example, menstruating women were not allowed to touch the plough or the potter’s wheel in western India, or enter the groves where betel-leaves (paan) were grown in Bengal.

Question 4.
Discuss, with examples, the significance of monetary transactions during the period under consideration.
Solution :
The significance of monetary transactions during the period (sixteenth and seventeenth centimes) was substantial because the Mughal Empire was among the greatest empires that had managed to consolidate its power and resources. There was stability in the Ming (China), Safavid (Iran) and Ottoman (Turkey) empires. This stability led to create vibrant networks of overland trade from China to the Mediterranean Sea. The discovery of New World resulted in massive expansion of trade of India with Europe.

With the expansion of trade the importance of monetary transactions increased. The expansion of trade brought huge amount of bullion and silver into India where there was no natural resource of silver. This led to remarkable stability in the availability of metal currency, particularly in silver rupya in India. This facilitated an unprecedented expansion of minting of coins and the circulation of money in the economy. At the same time, there was no exchange of goods or barter system during this period. The payments were made in gold or silver coins. According to Giovanni Careri, all the gold and silver which circulates throughout the world, ultimately, comes into India due to its overseas trade. Thus a large amounts of cash transactions took place in the sixteenth and seventeenth centuries.

Question 5.
Examine the evidence that suggests that land revenue was important for the Mughal fiscal system.
Solution :
(i) Agriculture was the mainstay of the economy. Land Revenue collected was used to pay salaries and to meet different kinds of administrative expenses. So it was considered important to establish an administrative apparatus to ensure control over agricultural production.

(ii) Thus, before fixing land revenue, Mughal state first acquired specific information about the extent of agricultural lands and their produce.

(iii) Land revenue collection arrangements was consisted of two stages of assessment. These were Jama and hasil. Cultivators were given the choice to pay land revenue either in cash or kind. The state preferred to collect land revenue as cash. Attempts were made to maximize profits from the land revenue collection.

(iv) Both cultivated and cultivable lands were measured in each province to fix land revenue. According to a decree of Akbar, it was the responsibility of malguzar to make cultivator pay land revenue in kind and it was also kept open. Thus, it is clear from the evidence that the monetary transactions were very important. To continue this policy efforts by subsequent emperors like Aurangzeb continued to measure land for collection of land revenue.

Question 6.
To what extent do you think caste was a factor in influencing social and economic relations in agrarian society ?
Solution :
Agricultural production involved the intensive participation and initiative of the peasantry. There were different social groups, on the basis of caste and other factors, that were involved in agricultural expansion. This affected their social and economic relations in the agrarian society in the following ways :

1. Deep inequalities on the basis of caste and other caste like distinctions made the cultivators a highly heterogeneous group.
2. Among those who tilled the land, there was a sizeable number who worked as menials or agricultural labourers (majur).
3. There was abundance of cultivable land but inspite of this certain caste groups were assigned menial tasks and were relegated to poverty. Such groups comprised a large section of the village population. They had the least resources and were constrained by their position in the caste hierarchy like the Dalits of modem India.
4. In Muslim communites too menials like halalkhoran (scavengers) were housed outside the boundaries of the village. The mallahzadas (sons of boatmen) in Bihar were comparable to slaves.

Thus, there was a direct correlation between caste, poverty and social status at the lower level of society. It was, however, not so at the intermediate levels. For example, in Marwar, Rajputs were considered peasants like Jats who were accorded a lower status in the caste hierarchy. The Gauravas, who cultivated land around Vrindavan sought Rajput status in the seventeenth century. Ahirs, Gujars and Malis rose in the hierarchy due to the profitability of cattle rearing and horticulture.

Question 7.
How were the lives of forest dwellers transformed in the sixteenth and seventeenth centuries ?
Solution :
The forest dwellers were people who earned their livelihood by gathering of forest produce, hunting and shifting agriculture. These activities changed according to seasons. For example, the Bhils collected forest produce in the spring. They did fishing in the summer, cultivated during the monsoon months. They did hunting in the winter and autumn. Such a division of activities presumed and perpetuated mobility which was a distinctive feature of the forest dwellers. However, their lives were transformed in the sixteenth and seventeenth centuries in the following ways :

1. In the sixteenth and seventeenth centuries, the state required elephants for the army. So, the peshkash – a form of tribute collected by the Mughal state – in the form of elephants too.
2. In the Mughal political ideology, the hunt symbolised the overwhelming concern of the state to ensure justice to all the subjects, rich and poor. Thus, during hunting expeditions, the emperor personally attended to the grievances of the people. Such hunting expeditions affected the lives of the forest dwellers.
3. Forests were cleaned for agricultural settlements. The spread of commercial agriculture impinged on the lives of forest dwellers, who lived on forest products like honey, beeswax and gum lac. Gum lac was exported from India. Elephants were captured and sold. There was [ exchange of commodities through barter too. All this changed due to commercial agriculture and agricultural settelments.
4. Social factors too transformed the lives of forest dwellers. For example, chieftains of many tribes had become zamindars, some even became kings. They built up their armies and demanded that their fraternity to provide military service. In Assam, the Ahom kings had their paiks. They were people who obliged to render military service in exchange for land. Not only this the capture of wild elephants was declared a royal monopoly by the Ahom kings.
5. With the establishment of tribal kingdoms in the north-east, war became a common feature.
6. The cultural influences as that of sufi saints encouraged the forest-dwellers particularly agricultural communities to accept Islam.

Question 8.
Examine the role played by zamindars in Mughal India.
Solution :
Zamindars played a significant role in Mughal India as mentioned below :

1. The zamindars had landed properties and enjoyed certain social and economic privileges due to their superior status in the society and due performance of certain services (khidmat) for the state.
2. They had milkiyat lands which were cultivated for the private use of zamindars with the help of hired or servile labour. The zamindars could sell, bequeath or mortgage these lands at will.
3. The zamindars collected revenue on behalf of the state. They were compensated for this financially.
4. They had military resources such as armed contingent and fortresses (qilachas).
5. In the social hierarchy, the zamindars constituted its very narrow apex.
6. Contemporary documents give an impression that conquest may have been source of the origin of some zamindaris. A powerful military chieftain often dispossessed weaker people and expanded his zamindari.
7. Zamindars spearheaded the colonisation of agricultural land. They helped in settling cultivators by providing them with the means of cultivation, including cash loans. The buying and selling of zamindaris accelerated the process of monetisation in the countryside. Zamindars sold the produce from their milkiyat lands and established markets (haats) where peasants came to sell their produce too.
8. Although the zamindars were considered as an exploitative class but their relationship with the peasants were based on reciprocity, paternalism and patronage because the bhakti saints did not portray them as exploiters or oppressors of peasantry. Not only this, in a large ‘ number of agrarian uprisings in north India in the seventeenth century, zamindars often received the support of the peasantry in their struggle against the state.

Question 9.
Discuss the ways in which panchayats and village headmen regulated rural , society.
Solution :
Panchayats and village headmen regulated the rural society in the following ways :

1. The village panchayat was an assembly of elders. Its decisions were binding on the members.
2. The panchayat was headed by a headman known as muqaddam or mandal. The headman supervised the preparation of accounts, assisted by the accountant or patwari of the panchayat.
3. The panchayat ensured that the caste boundaries among the various communities inhabitating the village were upheld. In eastern India all marriages were held in the presence of the mandal or headman. Thus, the headman was to oversee the conduct of the members of the village community “chiefly to prevent any offence against their caste”.
4. Panchayats had the authority to levy fines and inflict serious punishments such as expulsion from the community. Such punishment was given as a deterrant to violation of caste norms.
5. There were Jati panchayats of each caste. In Rajasthan, Jati panchayats arbitrated civil disputes between members of different castes. They decided the disputes related to claims on lands and marriages. Generally, the state respected the decisions of Jati panchayats.
6. Sometimes petitions were presented to the panchayat complaining about extortionate taxation or the demand for unpaid labour (begar) imposed by the “superior” castes or officials of the state. These were submitted by the lower classes because they regarded the village panchayat as the court of appeal that would ensure that the state carried out its moral obligations and guaranteed justice. In such cases, the panchayats often suggested compromise and reconciliation. In case of failure of compromise, the peasants generally deserted the village because there was abundance of uncultivated land available in the villages.

We hope the NCERT Solutions for Class 12 History Chapter 8 Peasants, Zamindars and the State Agrarian Society and the Mughal Empire help you. If you have any query regarding NCERT Solutions for Class 12 History Chapter 8 Peasants, Zamindars and the State Agrarian Society and the Mughal Empire, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 Physics Chapter 12 Atoms

NCERT Solutions for Class 12 Physics Chapter 12 Atoms are part of NCERT Solutions for Class 12 Physics. Here we have given. NCERT Solutions for Class 12 Physics Chapter 12 Atoms.

Board	CBSE
Textbook	NCERT
Class	Class 12
Subject	Physics
Chapter	Chapter 12
Chapter Name	Atoms
Number of Questions Solved	17
Category	NCERT Solutions

Question 1.
Choose the correct alternative from clues given at end of each statement:

1. The size of the atom in Thomson’s model is the atomic size in Rutherford’s model.(much greater than/no different from/much less than.)
2. In the ground state of…………… electrons are in stable equilibrium, while in ……………..  electrons always experience a net force. (Thomson’s model/Rutherford’s model.)
3. A classical atom based on…………. is doomed to collapse. (Thomson’s model/Rutherford’s model.)
4. An atom has a nearly continuous mass distribution in a………….. but has a highly non­uniform mass distribution in (Thomson’s model/Rutherford’s model.)
5. The positively charged part of the atom possesses most of the mass in…………. (Rutherford’s model/both the models.)

Answer:

1. no different from
2. Thomson’s model; Rutherford’s model.
3. Rutherford’s model.
4. Thomson’s model, Rutherford’s model.
5. both the models.

Question 2.
Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at a temperature 14 K). What results do you expect?
Answer:
The nucleus of a hydrogen atom is a proton. The mass of it is 1.67 x 10^-27 kg, whereas the mass of an incident α-particle is 6.64 x 10^-27 kg. Because the scattering particle is more massive than the target nuclei (proton). the α-particle won’t bounce back in even in a head-on collision. It is similar to a football colliding with a tennis ball at rest. Thus, there would be no large-angle scattering.

Question 3.
What is the shortest wavelength present in the Paschen series of spectral lines?
Answer:
The wavelength of the spectral lines forming the Paschen series is given by

Question 4.
A difference of 2.3 eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom transits from the upper level to the lower level?
Answer:

Question 5.
The ground state energy of the hydrogen atom is -13.6 eV. What are the kinetic and potential energies of the electron in this state?
Answer:
K.E. = -E (Total energy)
= -(-13.6) = 13.6 eV
P.E. = 2 X E = 2 X (-13.6)
= -27.2 eV

Question 6.
A hydrogen atom initially in the ground level absorbs a photon which excites it to the n = 4 level. Determine the wavelength and frequency of the photon.
Answer:
We know, the energy of an electron in the nth orbit of a hydrogen atom is given by

Question 7.
(a) Using Bohr’s model, calculate the speed of the electron in a hydrogen atom in the n = 1, 2, and 3 levels.
(b) Calculate the orbital period in each of these levels.
Answer:
(a) Speed of an electron in nth orbit of a hydrogen atom is given by

Question 8.
The radius of the innermost electron orbit of a hydrogen atom is 5.3 x 10^-11 m. What are the radii of the n = 2 and n = 3 orbits?
Answer:
We know, the radius of the nth orbit of a hydrogen atom is given by r_n = r₀n², where r₀ = 5.3 x 10^-u m is the radius of the innermost orbit of the hydrogen atom.
When n = 2, r₂ = 5.3 x 10^-u x 4
= 2.12 x 10-¹⁰m
When n = 3,
= 5.3 x 10-¹¹ x 9
= 4.77 x 10-¹⁰m.

Question 9.
A 12.75 eV electron beam is used to bombard gaseous hydrogen at room temperature. What series of wavelengths will be emitted?
Answer:

Question 10.
In accordance with Bohr’s model, And the quantum number that characterizes the earth’s revolution around the sun in an orbit of radius 1.5 x 10¹¹ m with an orbital speed
3 x 10¹⁴ m s^-1. (Mass of earth = 6.0 x 10²⁴ kg.)
Answer:
According to Bohr’s postulate of quantization of angular momentum

Question 11.
Answer the following questions, which help you understand the difference between Thomson’s model and Rutherford’s model better.
(a) Is the average angle of deflection of a-particles by a thin gold foil predicted by Thomson’s model much less, about the same, or much greater than that predicted by Rutherford’s model?
(b) Is the probability of backward scattering (i.e., scattering of a-particles at angles greater than 90°) predicted by Thomson’s model much less, about the same, or much greater than that predicted by Rutherford’s model?
(c) Keeping other factors fixed, it is found experimentally that for small thickness t, the number of a-particles scattered at moderate angles is proportional to What clue does this linear independence on t provide?
(d) In which model is it completely wrong to ignore multiple scattering for the calculation of the average angle of scattering of a-particles by a thin foil?
Answer:
(a) About the same
(b) Much less
(c) It suggests that the scattering is predominantly due to a single collision, because the chance of a single collision increases linearly with the number of target atoms, and hence linearly with thickness.
(d) In Thomson’s model, a single collision causes very little deflection. The observed average scattering angle can be explained only by considering multiple scattering. So it is wrong to ignore multiple scattering in the Thomson model. In Rutherford’s model, most of the scattering comes through a single collision and multiple scattering effects can be ignored as a first approximation.

Question 12.
The gravitational attraction between electron and proton in a hydrogen atom is weaker than the Coulomb attraction by a factor of about 10^-40. An alternative way of looking at this fact is to estimate the radius of the first Bohr orbit of a hydrogen atom if the electron and proton were bound by gravitational attraction. You will find the answer interesting.
Answer:
If electron and proton were bound by gravitational attraction, then

It is astonishing this value of r is much greater than the size of the universe.

Question 13.
Obtain an expression for the frequency of radiation emitted when a hydrogen atom
de-excites from the level it to level (n – 1). For large it, shows that this frequency equals the classical frequency of revolution of the electron in the orbit.
Answer:
The energy of an electron in the nth orbit of a hydrogen atom is given by

i.e. frequencies are equal. This is called Bohr’s correspondence principle.

Question 14.
Classically, an electron can be in any orbit around the nucleus of an atom. Then what determines the typical atomic size? Why is an atom not, say, a thousand times bigger than its typical size? The question had greatly puzzled Bohr before he arrived at his famous model of the atom that you have learned in the text. To stimulate what he might well have done before his discovery, let us play as follows with the basic constants of nature and see if we can get a quantity with the dimensions of length that is roughly equal to the known size of an atom (~ 10-¹⁰m).
(a) Construct a quantity with the dimensions of length from the fundamental constants e, m_e, and c. Determine its numerical value.
(b) You will find that the length obtained in («) many orders of magnitude smaller than the atomic dimensions. Further, it involves c. But energies of atoms are mostly in a non-relativistic domain where c is not expected to play any role. This is what may have suggested Bohr discard c and look for something else’ to get the right atomic size. Now, the Planck’s constant h had already made its appearance elsewhere. Bohr’s great insight lay in recognizing that h, m_e, and e will yield the right atomic size. Construct a quantity with the dimension of length from h, m_g, and e and confirm that its numerical value has indeed the correct order of magnitude.
Answer:
(a) Here, the dimensional formula of e is A¹T¹, the dimensional formula of m_e is M¹, dimensional formula

Question 15.
The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV.
(a) What is the kinetic energy of the electron in this state?
(b) What is the potential energy of the electron in this state?
(c) Which of the answers above would change if the choice of the zero of potential energy is changed?
Answer:
(a) K.E. = -E = – (-3.4 eV) = 3.4 eV
E. = 2E = 2 x (-3.4 eV)
= -6.8 eV
(b) Kinetic energy does not depend upon the choice of zero potential energy. Therefore, its value remains unchanged. However, the potential energy gets changed with the change in the zero levels of potential energy.

Question 16.
If Bohr’s quantisation postulate (angular momentum = nh/2π) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why then do we never speak of quantization of orbits of planets around the sun?
Answer:
Applying Bohr’s quantization postulate,

i.e., n is very large. Since n is very large, the difference between the two successive energy or angular momentum levels is very small and the levels may be considered continuous.

Question 17.
Obtain the first Bohr’s radius and the ground state energy of a ‘muonic hydrogen atom’ (i.e. an atom in which a negatively charged muon (μ^-1) of mass about 207 m_e orbits around a proton).
Answer:
Here the mass of the particle revolving around the proton is

We hope the NCERT Solutions for Class 12 Physics Chapter 12 Atoms, help you. If you have any query regarding NCERT Solutions for Class 12 Physics Chapter 12 Atoms, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 History Chapter 15 Framing the Constitution The Beginning of a New Era are part of NCERT Solutions for Class 12 History. Here we have given NCERT Solutions for Class 12 History Chapter 15 Framing the Constitution The Beginning of a New Era.

Board	CBSE
Textbook	NCERT
Class	Class 12
Subject	History
Chapter	Chapter 15
Chapter Name	Framing the Constitution The Beginning of a New Era
Number of Questions Solved	8
Category	NCERT Solutions

NCERT Solutions for Class 12 History Chapter 15 Framing the Constitution The Beginning of a New Era

Question 1.
What were the ideals expressed in the Objectives Resolution ?
Solution :
The “Objectives Resolution” outlined the ideals of the Constitution of Independent India as mentioned below :

• Independent sovereign republic : India will be an independent state without any foreign or internal control. Its head will be elected by the people.
• Justice, equality and freedom : It will guarantee its citizens justice, equality and freedom.
• Safeguards for minorities : It assured that “adequate safeguards shall be provided for minorities, backward and tribal areas, and Depressed and Other Backward Classes”.

Question 2.
How was the term minority defined by different groups?
Solution :
N.G. Ranga, a socialist who had been a leader of the peasant movement, urged that the term minorities be interpreted in economic terms. The real minorities were the poor and the downtrodden. Some considered that the real minorities were the masses of our country who were so depressed and oppressed that they were ot even able to take advantage of the ordinary civil rights. Singh spoke eloquently on the need to protect the tribes, and ensure conditions that could help them come up to the level of the general population.

Question 3.
What were the arguments in favour of greater power to the provinces ?
Solution :
The following arguments were given in favour of greater power to the provinces :

1. K. Santhanam stated that by giving more powers to the Centre, we could not make it strong because in such a situation, the Centre would be overburdened with responsibilities. It would not be able to function effectively. On the other hand, if the Centre was relieved of some functions or powers it could function effectively and become stronger.
2. He argued that weak status would cripple them. Their financial position would be weaker and without finances they would not be able to take up any project for development. They would have to depend on the central aid for education, sanitation and other welfare work for the people. He added a strong centre might lead the states to “revolt against the Centre” in the future.
3. A member from Orissa warned that “the Centre is likely to break” since powers had been excessively centralised under the Constitution.

Question 4.
Why did Mahatma Gandhi think Hindustani should be the national language?
Solution :
In view of Mahatma Gandhi Hindustani was a language that the common people could easily understand. Hindustani was a blend of Hindi and Urdu. It was also popular among a large section of the people. Moreover, it was a composite language enriched by the interaction of diverse cultures. Words and terms from many different languages got incorporated into this language over the years. It made this language easily understandable by people from various regions.
As per Mahatma Gandhi Hindustani would be the ideal language of communication between the communities. It would help to unify Hindus and Muslims and the people from north and south. Language came to be associated with the politics of religious identities from the end of the 19th century. But Mahatma Gandhi retained his faith in the composite character of Hindustani.

Question 5.
What historical forces shaped the vision of the Constitution?
Solution :
Historical forces that shaped the vision of the Constitution were as given below :

1. Historic efforts in the past : Nehru in his famous speech of 13 December 1946 referred to the American and French Revolutions. He thus linked the making of the Indian Constitution with the revolutionary moments in the past. But at the same time he emphasised not to copy the west but to learn from their experiments, achievements and failures.
2. The will of the people : Nehru stated that the source of the Constituent Assembly was its strength i.e., the will of the people. So, members always kept in mind that passions that lay in the hearts of the masses of the Indian people and tried to fulfil them. Thus, Constituent Assembly was expected to represent the people.
3. India, a large country with diversities : India is a large country with different religions, castes, communities, languages and groups. It was necessary to keep all united. So, the Constitution was prepared keeping in mind these diversities.
4. Protection of minorities : There were minorities and depressed classes. It was necessary to protect their interests. Gandhiji had already started movement for upliftment of the Harijan. Thus, there were debates in the Assembly and provisions were incorporated for their protection and upliftment.
5. Period of violence : There were riots and violence and communal frenzy. Under these circumstances it was necessary to have a strong Centre. There were arguments in favour of and against it. But ultimately more powers were given to the Centre.
6. Problem of princely states : There were more than five hundred princely states. To accommodate them, it was absolutely necessary to have a federal system of government.

Question 6.
Discuss the different arguments made in favour of protection of the oppressed groups.
Solution :
The different arguments made in favour of protection of the oppressed groups were as mentioned below :

1. It was argued that the problem of the “Untouchables” could not be resolved through protection and safeguards alone. Their disabilities were caused by the social norms and the moral values of caste society that had used their services and labour but kept them at a social distance.
2. J. Nagappa from Madras pointed out that the suffering of the Depressed Classes was i due to their systematic marginalisation and not due to their numerical insignificance. They had
   no access to education, or share in the administration.
3. K.J. Khanderkar from the Central Provinces argued that the Depressed Classes had been suppressed for thousands of years to such an extent that their bodies and minds were not able to march forward.

Question 7.
What connection did some of the members of the Constituent Assembly make between the political situation of the time and the need for a strong Centre ?
Solution :
The Constitution of India was framed between December 1946 and December 1949. It was a trouble-some time. There were riots and violence. There was the rising of the ratings of the Royal India Navy in Bombay and other cities in the spring of 1946. The violence culminated in the massacres that accompanied the transfer of populations when the Partition of India was announced. Some members of the Constituent Assembly made connection between the above political situation of the time and the need for a strong Centre as mentioned below :

1. Referring to riots and violence in the country, many members had repeatedly stated that the powers of the Centre had to be greatly strengthened to enable it to stop the communal frenzy.
2. Gopalaswami Ayyangar declared that “the Centre should be made as strong as possible”.
3. Balakrishna Sharma from the United Provinces reasoned at length that only a strong Centre could plan for the well-being of the country, mobilise the available economic resources and establish a proper administration.

Question 8.
How did the Constituent Assembly seek to resolve the language controversy ?
Solution :
There were two main views about the language of the nation as mentioned below :

1. A plea for Hindi : R.V. Dhulekar, from the United Provinces made a strong plea that Hindi be used as the language of making the constitution. He wanted Hindi to be declared a National Language.
2. The fear of domination : Shrimati Durgabai from Madras explained her worries. She informed the house that there was strong opposition against Hindi in the South. She stated
   that the erosion of inclusive and composite character of Hindustani was bound to create anxieties and fears amongst different language groups.

In view of the above differences, some members appealed for a spirit of accommodation and asked the members not to push the cause of Hindi aggressively. Thus, the language controversy was solved in the following way :

• Hindi in the Devanagari script would be the official language.
• Transition to Hindi would be gradual.
• For the first fifteen years, English would continue to be used for all official purposes.
• Each province was allowed to choose one of the regional languages for official work within the province.

Thus, referring to Hindi as the official rather that of the national language it was hoped that it would be acceptable to all.

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