MCQ Questions for ISC Class-12 Ch-6 General Principal and Process of Isolation of Element

MCQ / Objective Type Questions for ISC Class-12 Chapter-6 General Principal and Process of Isolation of Element. These MCQ  / Objective Type Questions is based on latest reduced syllabus according 2021-22 session on bifurcated pattern. Visit official website CISCE for detail information about ISC Board Class-12 Chemistry.

MCQ / Objective Type Chemistry Questions for ISC Class-12 Chapter-6 General Principal and Process of Isolation of Element

Board ISC
Class  12th (XII)
Subject Chemistry
Chapter-6 General Principal and Process of Isolation of Element.
Syllabus  on bifurcated syllabus (after reduction)
Session 2021-22
Topic MCQ / Objective Type Question

Chapter-6 General Principal and Process of Isolation of Element MCQ / Objective Type Chemistry Questions for ISC Class-12 

Question 1 : Choose the correct option of temperature at which carbon reduces FeO to iron and produces CO.(a) Below temperature at point A.

(b) Approximately at the temperature corresponding to point A.
(c) Above temperature at point A but below temperature at point D.
(d) Above temperature at point A.
Answer :  (d) Above temperature at point A.
Question 2 : Below point ‘A’ FeO can

(a) be reduced by carbon monoxide only.

(b) be reduced by both carbon monoxide and carbon.

(c) be reduced by carbon only.

(d) not be reduced by both carbon and carbon monoxide.

Answer : (a) be reduced by carbon monoxide only.

Question 3 : For the reduction of FeO at the temperature corresponding to point D, which of the following statements is correct?

(a) ΔG value for the overall reduction reaction with carbon monoxide is zero.

(b) ΔG value for the overall reduction reaction with a mixture of 1 mol carbon and 1 mol oxygen is positive.

(c) ΔG value for the overall reduction reaction with a mixture of 2 mol carbon and 1 mol oxygen will be positive.

(d) ΔG value for the overall reduction reaction with carbon monoxide is negative.

Answer : (a) ΔG value for the overall reduction reaction with carbon monoxide is zero.

Question 4 : 4M + 8CN + H2O + O2 → 4[M(CN)2] + 4OH, the metal M is

(a) copper

(b) iron

(c) gold

(d) Zinc

Answer: (c) gold

Question 5 : Heating ore with carbon in the absence of air is known as:

(a) reduction

(b) carbon-reduction

(c) smelting

(d) Roasting

Answer: (c) smelting

Question 6 : The electrolytic reduction technique is used in the extraction of

(a) Highly electronegative elements.

(b) Highly electropostive elements.

(c) Metalloids.

(d) Transition metals.

Answer: (b) Highly electropostive elements.

Question 7 : In the commercial electrochemical process for aluminium extraction, electrolyte used is

(a) Al(OH)3 is NaOH solution.

(b) An aqueous solution of Al2 (SO4)3.

(c) A molten mixture of Al2O3 and Na3AlF6.

(d) A molten mixture of Al2O3 and Al(OH)3.

Answer: (c) A molten mixture of Al2O3 and Na3AlF6.

Question 8 : Which ore can be best concentrated by froth floatation process?

(a) Malachite

(b) Cassiterite

(c) Galena

(d) Magnetite

Answer: (c) Galena

Question 9 :  Concentration of sulphide ore is done by

(a) froth flotation process

(b) electrolysis

(c) roasting

(d) None of these

Answer: (a) froth flotation process

Question 10 : Malachite is an ore of

(a) iron

(b) copper

(c) zinc

(d) Sliver

Answer: (b) copper

Question 11 : In …………… the metallurgy of aluminium

(a) Al3+ is oxidised to Al (s).

(b) graphite anode is oxidised to carbon monoxide and carbon dioxide.

(c) oxidation state of oxygen changes in the reaction at anode.

(d) oxidation state of oxygen changes in the overall reaction involved in the process.

Answer: (b) graphite anode is oxidised to carbon monoxide and carbon dioxide.

Question 12 : Electrolytic refining is used to purify which of the following metals?

(a) Cu and Zn

(b) Ge and Si

(c) Zr and Ti

(d) Zn and Hg

Answer: (a) Cu and Zn

Question 13 :Extraction of gold and silver involves leaching the metal with CN ion. The metal is recovered by

(a) displacement of metal by some other metal from the complex ion.

(b) roasting of metal complex.

(c) calcination followed by roasting.

(d) thermal decomposition of metal complex.

Answer: (a) displacement of metal by some other metal from the complex ion.

Question 14: In the extraction of copper from sulphide ore, the metal is formed by reduction of Cu2O with

(a) FeS

(b) CO

(c) Cu2S

(d) SO2

Answer: (c) Cu2S

Question 15: The method of zone refining of metals is based upon the principle of

(a) greater solubility of the impurity in molten state than in solid

(b) greater mobility of pure metal than impurity

(c) higher melting point of impurity than that of pure metal.

(d) greater noble character of solid metal than that of the impurity

Answer: (a) greater solubility of the impurity in molten state than in solid

Question 16: Electrolytic reduction of Al2O3 to Al by Hall- Herault process is carried out

(a) in presence of NaCl.

(b) in presence of fluorite.

(c) in presence of cryolite which forms a melt with lower melting point.

(d) in presence of cryolite which forms a melt with high melting point.

Answer: (c) in presence of cryolite which forms a melt with lower melting point.

Question 17: The chemical composition of ‘slag’ formed during the melting process in the extraction of copper is

(a) Cu2O + FeS

(b) FeSiO3

(c) CuFeS2

(d) Cu2S + FeO

Answer: (b) FeSiO3

Question 18: Bessemer converter is used in the manufacture of

(a) Pig iron

(b) Steel

(c) Wrought iron

(d) Cast iron

Answer: (b) Steel

Question 19: Formula of copper pyrite is

(a)Cu2S

(b) CuFeS

(c) CuFeS2

(d) Cu2Fe2S2

Answer: (c) CuFeS2

Question 20: Ore of aluminium is

(a) bauxite

(b) hematite

(c) dolomite

(d) None of these

Answer: (a) bauxite

Question 21: 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: (a) concentration, dressing, benefaction

Question 22: A number of elements are available in earth’s crust but most abundant elements are

(a) Al and Fe

(b) Al and Cu

(c) Fe and Cu

(d) Cu and Ag

Answer: (a) Al and Fe

Question 23:. Zone refining is based on the principle that

(a) impurities of low boiling metals can be separated by distillation.

(b) impurities are more soluble in molten metal than in solid metal.

(c) different components of a mixture are differently adsorbed on an adsorbent.

(d) vapours of volatile compound can be decomposed in pure metal.

Answer:(b) impurities are more soluble in molten metal than in solid metal.

Question 24: In the extraction of copper from its sulphide ore, the metal is formed by the reduction of Cu2O with

(a) FeS

(b) CO

(c) Cu2S

(d) SO2

Answer: (c) Cu2S

Question 25: In the electrolytic method of obtaining aluminium from purified bauxite, cryolite is added to the charge in order to:

(a) lower the melting point of bauxite

(b) dissolve bauxite and render it a conductor of electricity

(c) protect aluminium produced from oxygen

(d) minimise the heat loss due to radiation

Answer: (b) dissolve bauxite and render it a conductor of electricity

Question 26: Extraction of zinc from zinc blende is achieved by

(a) electrolytic reduction

(b) roasting followed by reduction with carbon

(c) roasting followed by reduction with another metal

(d) roasting followed by self-reduction

Answer: (b) roasting followed by reduction with carbon

Question 27:  In electrorefining of copper some gold is produced as:

(a) cathode mud

(b) anode mud

(c) cathode deposit

(d) anode deposit

Answer: (b) anode mud

Question 28:  The purest form of iron is:

(a) cast iron

(b) pig iron

(c) wrought iron

(d) steel

Answer: (c) wrought iron

Question 29:  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: (d) gravity separation

Question 30:  The oil used as frothing agent in froth floatation process is

(a) coconut oil

(b) castor oil

(c) palmitic oil

(d) pine oil

Answer: (d) pine oil

Question 31:  For which of the following ores froth floatation method is used for concentration?

(a) Haematite

(b) Zinc blende

(c) Magnetite

(d) Camallite

Answer: (b) Zinc blende

Question 32:  In the extraction of chlorine by electrolysis of brine

(a) oxidation of Cl ion to chlorine gas occurs.

(b) reduction of Cl ion to chlorine gas occurs.

(c) for overall reaction ΔGΘ has negative value.

(d) a displacement reaction takes place.

Answer: (c) for overall reaction ΔGΘ has negative value.

Question 33:  When copper ore is mixed with silica in a reverberatory furnace, copper matte is produced. The copper matte contains

(a) sulphides of copper (II) and iron (II)

(b) sulphides of copper (II) and iron (III)

(c) sulphides of copper (I) and iron (II)

(d) sulphides of copper (I) and iron (III)

Answer: (c) sulphides of copper (I) and iron (II)

Question 34: Which of the following reactions is an example of auto reduction?

(a) Fe3O4 + 4C0 → 3Fe + 4CO2

(b) Cu2O + C → 2Cu + CO

(c) Cu2+(aq) + Fe(s) → Cu(s) + Fe2+(aq)

(d) Cu2O + 1/2 Cu2S → 3Cu + 1/2 SO2

Answer: (d) Cu2O + 1/2 Cu2S → 3Cu + 1/2 SO2

Question 35:  Which of the following metals is not extracted by leaching?

(a) Aluminium

(b) Mercury

(c) Silver

(d) Gold

Answer: (b) Mercury

Question 36: Sulphide ore of zinc/copper is concentrated by

(a) floatation process

(b) electromagnetic process

(c) gravity separation

(d) distillation

Answer: (a) floatation process

Question 37: Blister copper is

(a) impure copper

(b) obtained in self reduction process during bessermerisation

(c) Both are correct

(d) None is correct

Answer: (c) Both are correct

Question 38: Which of the following slags is produced during extraction of iron?

(a) CaSiO3

(b) FeSiO3

(c) MgSiO3

(d) ZnSiO3

Answer: (a) CaSiO3

Question 39: Which of the following oxides cannot be reduced by hydrogen?

(a) Ferric oxide

(b) Aluminium oxide

(c) Zinc oxide

(d) Cupric oxide

Answer: (b) Aluminium oxide

Question 40: In which of the following minerals Al is not present?

(a) Cryolite

(b) Mica

(c) Feldspar

(d) Fluorspar

Answer: (d) Fluorspar

Question 41: In the metallurgy of iron from haematite, limestone is added to act as

(a) flux

(b) slag

(c) a reducing agent

(d) an oxidising agent

Answer: (a) flux

Question 42: Which of the following ores is concentrated by the froth floatation process?

(a) Haematite

(b) Magnetite

(c) Copper pyrite

(d) Bauxite

Answer: (c) Copper pyrite

Question 43: In blast furnace iron oxide is reduced by

(a) silica

(b) carbon monoxide

(c) carbon

(d) lime stone

Answer: (b) carbon monoxide

Question 44: 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: (a) Carbon

Question 45: In a thermite process is used as reducing agent.

(a) Zn

(b) Al

(c) Mn

(d) Fe

Answer: (b) Al

Question 46: The metal always found in free state is

(a) Gold

(b) Silver

(c) Copper

(d) Sodium

Answer: (a) Gold

Question 47 : Bauxite is an ore of

(a) Aluminium

(b) Calcium

(c) Copper

(d) Zinc

Answer: (a) Aluminium

Question 48:  Malachite is an ore of

(a) Hg

(b) Cu

(c) Sn

(d) Mn

Answer: (b) Cu

Question 49: The process employed for the concentration of sulphide ore is

(a) Froth floatation

(b) Roasting

(c) Electrolysis

(d) Calcination

Answer: (a) Froth floatation

Question 50: Ellingham diagram represents change of

(a) ΔG with temperature

(b) ΔH with temperature

(c) ΔG with pressure

(d) (ΔG – TΔS) with temperature

Answer: (a) ΔG with temperature

-: End of MCQ / Objective Type Questions for ISC Class-12 Chapter-6 General Principal and Process of Isolation of Element :-


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