MCQ Questions for Class 11 Chemistry Chapter 9 Hydrogen with Answers

Answer: (b) Liquid
Explanation:
Hydrogen peroxide is the simplest kind of peroxide available (oxygen-oxygen single bond). It is a colourless liquid and is used in aqueous solution for safety reasons. It acts as a bleaching agent and is also used as a disinfectant. Concentrated hydrogen peroxide is a very reactive oxygen species and is used as a propellant in rocketry. The chemical formula for hydrogen peroxide is H₂O₂.

Answer: (b) 3.8°C

Answer: (b) 90%
Explanation:
H₂O₂ is used as an oxidant for rocket fuel. Usually, 90% concentration of H₂O₂ is used.

Answer: (c) Interstitial Hydrides
Explanation:
Interstitial hydrides are non- stoichiometric hydrides and thus deficit in hydrogen. Transition and inner transition elements at relevant temperature absorb hydrogen into the interstices of their lattices to yield metal like hydrides.

Answer: (b) HCl + O₂
Explanation:
H₂O₂ + Cl₂ → 2HCl + O₂

Answer: (a) 0 to 4°C
Explanation:
Water show a wide range of anomalies compared to similar liquids or hydrides of other group 16 elements. One of the most talked-about anomalies is the formation of ice from liquid water and how the density changes when we cool the water.

O is a small atom and highly electronegative compared to Hydrogen. So O attracts the covalent clouds of O-H towards itself, thus making water a polar molecule. The hydrogen bonding in water molecules causes high boiling point and liquid state compared to other hydrides of group 16.

When we cool water from higher temperature, the density steadily decreases. At 4 degree C it is the highest. But below 4 degree C, The H-bonds break between the molecules and the molecules get drifted further apart, the volume increases and density decreases. The crystalline form of water is ice. At atmospheric pressure ice crystallises in the hexagonal form, but at very low temperatures it condenses to cubic form leaving gap between the structures, thus increasing the volume again.

Density of ice is less than that of water. Therefore, an ice cube floats on water. In winter season ice formed on the surface of a lake provides thermal insulation which ensures the survival of the aquatic life.

Answer: (d) All of the above
Explanation:
H₂O₂ show all these properties

Answer: (c) Nascent Hydrogen
Explanation:
A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe.

In everyday life on Earth, isolated hydrogen atoms (called “atomic hydrogen”) are extremely rare. Instead, a hydrogen atom tends to combine with other atoms in compounds, or with another hydrogen atom to form ordinary (diatomic) hydrogen gas, H₂. “Atomic hydrogen” and “hydrogen atom”

Answer: (d) 8.4
Explanation:
Strength =Normality ×Equivalent Weight of H₂O₂
= 1.5N × 1.7gL^-1 = 25.5gL^-1
2H₂O₂ → 2H₂O + O₂
68g 22400 mLat STP
68 g of H₂O gives = 22400 mL of O₂ at STP
25.5 gH₂O₂ gives = 2240068 × 25.5 = 8400 mL of O₂ at STP
25.5g of H₂O₂ is present in 1000 mL of H₂O₂ solution
1000 mL of H₂O₂ gives 8400 mL of O₂ at STP
1 mL of H₂O₂ gives 84001000 mL of O₂ at STP
= 8.4mL of O₂
Hence, volume strength of 1.5NH₂O₂ = 8.4 volume.
Or mass of H₂O₂ in 1.5N solution
= Equivalent Weight of H₂O₂ × 1.5N
= 17 × 1.5 = 25.5 g/L
Hence, volume strength of 1.5NH₂O₂ solution
= 22.4 × 25.568 = 8.4

Answer: (a) CO
Explanation:
Water gas is a combustion fuel containing carbon monoxide (CO) and hydrogen gas (H₂). Water gas is made by passing steam over heated hydrocarbons.

Answer: (c) 4
Explanation:
Hydrogen has three main isotopes; Protium (¹H), deuterium (²H) and tritium (³H). These isotopes form naturally in nature. Protium and deuterium are stable. Tritium is radioactive and has a half-life of about 12 years. Scientists have created four other hydrogen isotopes (4H to 7H), but these isotopes are very unstable and do not exist naturally.
The main isotopes of hydrogen are unique because they are the only isotopes that have a name.

Answer: (b) 3.8°C

Answer: (b) Liquid
Explanation:
Hydrogen peroxide is the simplest kind of peroxide available (oxygen-oxygen single bond). It is a colourless liquid and is used in aqueous solution for safety reasons. It acts as a bleaching agent and is also used as a disinfectant. Concentrated hydrogen peroxide is a very reactive oxygen species and is used as a propellant in rocketry. The chemical formula for hydrogen peroxide is H₂O₂.

Answer: (c) Black Suspension of Lead Sulphide(PbS)
Explanation:
Lead sulphide (black suspension) on reaction with hydrogen peroxide forms lead sulphate and water. Lead sulphate as well as water are colourless, therefore lead sulphite decolourises on addition of hydrogen peroxide.
PbS(s) + 4H₂O₂ (aq) → PbSO₄ (s) + 4H₂O (aq)

Answer: (c) 152
Explanation:
As reductant hydrogen peroxide oxidises to oxygen. H₂O₂ → O₂
​The change in oxidation number is 2
The molar mass = 34 g
Gram equivalent weight of H₂O₂ = (\(\frac{34}{2}\))
​= 17 g
Equivalent weight = 152

Answer: (a) Oxygen
Explanation:
The mass-abundance of the nine most abundant elements in the Earths crust is approximately: oxygen 46%, silicon 28%, aluminium 8.2%, iron 5.6%, calcium 4.2%, sodium 2.5%, magnesium 2.4%, potassium, 2.0%, and titanium 0 .61%.
Hydrogen is 0.14% on earths crust and other elements occur at less than 0.15%.

Answer: (c) Nascent Hydrogen
Explanation:
A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe.

In everyday life on Earth, isolated hydrogen atoms (called “atomic hydrogen”) are extremely rare. Instead, a hydrogen atom tends to combine with other atoms in compounds, or with another hydrogen atom to form ordinary (diatomic) hydrogen gas, H₂. “Atomic hydrogen” and “hydrogen atom”

Answer: (b) Reducing
Explanation:
Hydrogen acts as a good reducing agent means, when hydrogen gas is passed over hot metallic oxides of copper, lead, iron, etc. it removes oxygen from them and thus reduces them to their corresponding metal. Let us consider the following example, in each of which metallic oxide react with hydrogen. Metallic oxide act as oxidizing agents and hydrogen acts as a reducing agent.

Answer: (b) 50 ml
Explanation:
As 10 ml of oxygen is obtained at STP from H₂O₂ = 1 ml
Therefore, 500 ml of O₂ is obtained at STP = 50 ml

Answer: (a) Abundant
Explanation:
Hydrogen is considered as the most common and abundant element. The element Hydrogen has only one proton and one electron and is the only element which has no neutrons. Therefore it is considered as the simplest element in the universe and gives a valid reason for it to be the most abundant and common element in the universe. As per estimation from the Jefferson Lab, approximately 90 percent of the visible universe is framed by Hydrogen proving that being in the simplest form, this element is the most common and abundant element in the universe.