Check the below NCERT MCQ Questions for Class 12 Chemistry Chapter 6 General Principles and Processes of Isolation of Elements with Answers Pdf free download. MCQ Questions for Class 12 Chemistry with Answers were prepared based on the latest exam pattern. We have provided General Principles and Processes of Isolation of Elements Class 12 Chemistry MCQs Questions with Answers to help students understand the concept very well.

General Principles and Processes of Isolation of Elements Class 12 MCQs Questions with Answers

Question 1.
Concentration of sulphide ore is done by
(a) froth flotation process
(b) electrolysis
(c) roasting
(d) None of these

Answer

Answer: (a) froth flotation process


Question 2.
Malachite is an ore of
(a) iron
(b) copper
(c) zinc
(d) Sliver

Answer

Answer: (b) copper


Question 3.
Formula of copper pyrite is
(a)Cu2S
(b) CuFeS
(c) CuFeS2
(d) Cu2Fe2S2

Answer

Answer: (c) CuFeS2


Question 4.
Ore of aluminium is
(a) bauxite
(b) hematite
(c) dolomite
(d) None of these

Answer

Answer: (a) bauxite


Question 5.
Removal of the unwanted materials like sand, clays, etc. from the ore is known as ………., …….. or ……….
(a) concentration, dressing, benefaction
(b) separation, refining, gangue
(c) magnetic separation, purification, gangue
(d) washing, refining, amalgamation

Answer

Answer: (a) concentration, dressing, benefaction


Question 6.
For which of the following ores froth floatation method is used for concentration?
(a) Haematite
(b) Zinc blende
(c) Magnetite
(d) Camallite

Answer

Answer: (b) Zinc blende


Question 7.
The powdered ore is agitated with water or washed with running stream of water. The heavy ore particles and lighter impurities are separated. This method of concentration is known as
(a) metallurgy
(b) leaching
(c) froth floatation process
(d) gravity separation

Answer

Answer: (d) gravity separation


Question 8.
The oil used as frothing agent in froth floatation process is
(a) coconut oil
(b) castor oil
(c) palmitic oil
(d) pine oil

Answer

Answer: (d) pine oil


Question 9.
Which of the following metals is not extracted by leaching?
(a) Aluminium
(b) Mercury
(c) Silver
(d) Gold

Answer

Answer: (b) Mercury


Question 10.
Sulphide ore of zinc/copper is concentrated by
(a) floatation process
(b) electromagnetic process
(c) gravity separation
(d) distillation

Answer

Answer: (a) floatation process


Question 11.
Which of the following ores is concentrated by chemical leaching method?
(a) Cinnabar
(b) Argentite
(c) Copper pyrites
(d) Galena

Answer

Answer: (b) Argentite


Question 12.
How do we separate two sulphide ores by froth floatation method?
(a) By using excess of pine oil
(b) By adjusting proportion of oil to water or using depressant.
(c) By using some solvent in which one of the sulphides is soluble
(d) By using collectors and froth stabilisers like xanthates

Answer

Answer: (b) By adjusting proportion of oil to water or using depressant.


Question 13.
Common impurities present in bauxite are
(a) CuO
(b) ZnO
(c) CaO
(d) SiO2

Answer

Answer: (d) SiO2


Question 14.
An ore of tin containing FeCrO4 is concentrated by
(a) gravity separation
(b) magnetic separation
(c) froth floatation
(d) leaching

Answer

Answer: (b) magnetic separation


Question 15.
Which of the following ores cannot be concentrated by magnetic separation?
(a) Haematite
(b) Malachite
(c) Magnetite
(d) Siderite

Answer

Answer: (b) Malachite


Question 16.
The significance of leaching in the extraction of aluminium is
(a) it helps removing the impurities like SiO2, Fe2O3 etc. from the bauxite ore
(b) it converts the ore into oxide
(c) it reduces melting point of the ore
(d) it eliminates water from bauxite

Answer

Answer: (a) it helps removing the impurities like SiO2, Fe2O3 etc. from the bauxite ore


Question 17.
Which of the following metals is extracted using a silica lined convertor?
(a) Mg
(b) Al
(c) Cu
(d) Zn

Answer

Answer: (c) Cu


Question 18.
Which of the following sulphides when heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide?
(a) Cu2S
(b) FeS
(c) HgS
(d) ZnS

Answer

Answer: (c) HgS


Question 19.
Which of the following metals cannot be obtained by reduction of its metal oxide bv aluminium ?
(a) Cr
(b) Mn
(c) Fe
(d) Mg

Answer

Answer: (d) Mg


Question 20.
Heating pyrites to remove sulphur is called
(a) smelting
(b) calcination
(c) liquation
(d) roasting

Answer

Answer: (d) roasting


Question 21.
Impurities of sulphur, silicon and phosphorus can be removed from cast iron by adding
(a) carbon which reduces the impurities
(b) water which dissolves the impurities
(c) limestone which changes impurities into oxides and pass into slag
(d) iron oxide which reacts with impurities by forming slag

Answer

Answer: (c) limestone which changes impurities into oxides and pass into slag


Question 22.
In metallurgical process, aluminium acts as
(a) an oxidising agent
(b) a reducing agent
(c) acidic flux
(d) basic flux

Answer

Answer: (b) a reducing agent


Question 23.
Ellingham diagram represents change of
(a) ΔG with temperature
(b) ΔH with temperature
(c) ΔG with pressure
(d) (ΔG – TΔS) with temperature

Answer

Answer: (a) ΔG with temperature


Question 24.
During the extraction of haematite, limestone is added which acts as
(a) flux
(b) slag
(c) reducing agent
(d) gangue

Answer

Answer: (a) flux


Question 25.
In blast furnace iron oxide is reduced by
(a) silica
(b) carbon monoxide
(c) carbon
(d) lime stone

Answer

Answer: (b) carbon monoxide


Question 26.
From the Ellingham graph between Gibb’s energy and temperature, out of C and CO with is a better reducing agent for ZnO?
(a) Carbon
(b) CO
(c) Both of these
(d) None of these

Answer

Answer: (a) Carbon


Question 27.
In a thermite process is used as reducing agent.
(a) Zn
(b) Al
(c) Mn
(d) Fe

Answer

Answer: (b) Al


Question 28.
Blister copper is
(a) impure copper
(b) obtained in self reduction process during bessermerisation
(c) Both are correct
(d) None is correct

Answer

Answer: (c) Both are correct


Question 29.
Which of the following slags is produced during extraction of iron?
(a) CaSiO3
(b) FeSiO3
(c) MgSiO3
(d) ZnSiO3

Answer

Answer: (a) CaSiO3


Question 30.
Which of the following oxides cannot be reduced by hydrogen?
(a) Ferric oxide
(b) Aluminium oxide
(c) Zinc oxide
(d) Cupric oxide

Answer

Answer: (b) Aluminium oxide


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