Solved Example: General Principles and Processes of Isolation of Metals | Chemistry for JEE Main & Advanced PDF Download

 Page 1


JEE Solved Example on General Principles and 
Processes of Isolation of Metals 
Q1:  In presence of oxygen, removal of sulphur from an ore is included in 
(A) Calcination 
(B) Roasting 
(C) Smelting 
(D) Fluxing 
Ans:  (B) During roasting, air is blown to convert metal sulphides into metal oxides. 
F eS +
3
2
O
2
? F eO + SO
2
 
 
Q2:  In the extraction of copper from its sulphide ore, the metal is formed by reduction of ????
?? ?? 
with 
(A) ?????? 
(B) ? ?? 
(C) ????
?? ?? 
(D) ????
?? 
Ans: (C) Cu can be reduced by self-reduction. So, 
Cu
2
 S +
3
2
O
2
? Cu
2
O + SO
2
; 2 Cu
2
O + Cu
2
 S ? 6C u + SO
2
 
 
Q3:  Pyrolusite is a/an 
(A) Oxide ore 
(B) Sulphide ore 
(C) Carbide ore 
(D) Not an ore 
Ans:  (A) Pyrolusite ? Mn O
2
 
 
Q4: The metal always found in the free state is 
(A) ???? 
(B) ???? 
(C) ???? 
(D) ???? 
Ans:  (A) Ag, Au, Hg, Pt are chemically inert metals. 
 
 
Page 2


JEE Solved Example on General Principles and 
Processes of Isolation of Metals 
Q1:  In presence of oxygen, removal of sulphur from an ore is included in 
(A) Calcination 
(B) Roasting 
(C) Smelting 
(D) Fluxing 
Ans:  (B) During roasting, air is blown to convert metal sulphides into metal oxides. 
F eS +
3
2
O
2
? F eO + SO
2
 
 
Q2:  In the extraction of copper from its sulphide ore, the metal is formed by reduction of ????
?? ?? 
with 
(A) ?????? 
(B) ? ?? 
(C) ????
?? ?? 
(D) ????
?? 
Ans: (C) Cu can be reduced by self-reduction. So, 
Cu
2
 S +
3
2
O
2
? Cu
2
O + SO
2
; 2 Cu
2
O + Cu
2
 S ? 6C u + SO
2
 
 
Q3:  Pyrolusite is a/an 
(A) Oxide ore 
(B) Sulphide ore 
(C) Carbide ore 
(D) Not an ore 
Ans:  (A) Pyrolusite ? Mn O
2
 
 
Q4: The metal always found in the free state is 
(A) ???? 
(B) ???? 
(C) ???? 
(D) ???? 
Ans:  (A) Ag, Au, Hg, Pt are chemically inert metals. 
 
 
Q. 5 In the extraction of iron, the slag produced is? 
(A) ???? 
(B) ?????????? ?? 
(C) ?????? ???? ?? 
(D) ???? ?? ???? ?? 
Ans: (D) Ca O
 lime 
+ SiO
2
 silica 
? Ca S i O
3
 slag 
 
 
 
Q6: Which alloy of aluminium is used in aircraft industry 
(A) Duralumin 
(B) Magnalium 
(C) Nickeloy 
(D) alunico 
Ans: (A) Duralumin an alloy of aluminium is used in aircraft industry 
 
Q7:  The common impurities present in the bauxite ore are 
(A) ????
?? ?? ?? and ???? ?? 
(B) ????
?? ?? ?? and ?????? 
(C) ????
?? ?? ?? and ?? ???? ?? 
(D) ?? ???? ?? and ???? ?? 
Ans: (C) Bauxite ore impurities: - SiO
2
+ Fe
2
O
3
 
Acidic impuntities 
 
Q8:  The material used in solar cell contains 
(A) ???? 
(B) ???? 
(C) ???? 
(D) Cs 
Ans:  (A) Si is a semi-conductor. 
 
Q9:  Cyanide process is used for the extraction of: 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ???? 
Ans: (A) 
 
 
Page 3


JEE Solved Example on General Principles and 
Processes of Isolation of Metals 
Q1:  In presence of oxygen, removal of sulphur from an ore is included in 
(A) Calcination 
(B) Roasting 
(C) Smelting 
(D) Fluxing 
Ans:  (B) During roasting, air is blown to convert metal sulphides into metal oxides. 
F eS +
3
2
O
2
? F eO + SO
2
 
 
Q2:  In the extraction of copper from its sulphide ore, the metal is formed by reduction of ????
?? ?? 
with 
(A) ?????? 
(B) ? ?? 
(C) ????
?? ?? 
(D) ????
?? 
Ans: (C) Cu can be reduced by self-reduction. So, 
Cu
2
 S +
3
2
O
2
? Cu
2
O + SO
2
; 2 Cu
2
O + Cu
2
 S ? 6C u + SO
2
 
 
Q3:  Pyrolusite is a/an 
(A) Oxide ore 
(B) Sulphide ore 
(C) Carbide ore 
(D) Not an ore 
Ans:  (A) Pyrolusite ? Mn O
2
 
 
Q4: The metal always found in the free state is 
(A) ???? 
(B) ???? 
(C) ???? 
(D) ???? 
Ans:  (A) Ag, Au, Hg, Pt are chemically inert metals. 
 
 
Q. 5 In the extraction of iron, the slag produced is? 
(A) ???? 
(B) ?????????? ?? 
(C) ?????? ???? ?? 
(D) ???? ?? ???? ?? 
Ans: (D) Ca O
 lime 
+ SiO
2
 silica 
? Ca S i O
3
 slag 
 
 
 
Q6: Which alloy of aluminium is used in aircraft industry 
(A) Duralumin 
(B) Magnalium 
(C) Nickeloy 
(D) alunico 
Ans: (A) Duralumin an alloy of aluminium is used in aircraft industry 
 
Q7:  The common impurities present in the bauxite ore are 
(A) ????
?? ?? ?? and ???? ?? 
(B) ????
?? ?? ?? and ?????? 
(C) ????
?? ?? ?? and ?? ???? ?? 
(D) ?? ???? ?? and ???? ?? 
Ans: (C) Bauxite ore impurities: - SiO
2
+ Fe
2
O
3
 
Acidic impuntities 
 
Q8:  The material used in solar cell contains 
(A) ???? 
(B) ???? 
(C) ???? 
(D) Cs 
Ans:  (A) Si is a semi-conductor. 
 
Q9:  Cyanide process is used for the extraction of: 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ???? 
Ans: (A) 
 
 
Q10:  During smelting, an additional substance is added which combines with impurities to form a 
fusible product. It is known as 
(A) Slag 
(B) Mud 
(C) Gangue 
(D) Flux 
Ans: (D) Flux + Gangue ? slag. 
 
Q11:  Purification of silicon element used in semiconductors is done by 
(A) Zone refining 
(B) Heating 
(C) Froth floatation 
(D) Heating in vacuum 
Ans: (A) Zone refining: - Purification is done at microscopic level because we need ultra -purified 
element to use in semi-conductors. Zone refining is based on fractional crystallisation. 
 
Q12:  Aluminothermic process is used for metallurgy of 
(A) ???? 
(B) ???? 
(C) ???? 
(D) None of these 
Ans: (D) None of this elements can be reduced by Al but other example are Cr , Mn , Ti, etc. 
 
Q13:  In electrorefining of copper some gold is deposited as 
(A) Anode mud 
(B) Cathode mud 
(C) Cathode 
(D) Electrolyte 
Ans: (A) Anode mud are the elements which get deposited in the bottom of anode Eg. Ag, Au, Pt. 
 
Q14:  Poling process is used 
(A) For the removal of ????
?? ?? from ???? 
(B) For the removal of ????
?? ?? ?? from ???? 
(C) For the removal ????
?? ?? ?? from ???? 
(D) In all the above 
Ans: (A) Poling:- Molten metal is stirred with green anode poles which releases hydrocarbon (gas) 
which reduces the oxide e.g. Cu 
Cu
2
O + CO ? 2C u + CO
2
; Cu
2
O + H
2
? 2C u + H
2
O 
Page 4


JEE Solved Example on General Principles and 
Processes of Isolation of Metals 
Q1:  In presence of oxygen, removal of sulphur from an ore is included in 
(A) Calcination 
(B) Roasting 
(C) Smelting 
(D) Fluxing 
Ans:  (B) During roasting, air is blown to convert metal sulphides into metal oxides. 
F eS +
3
2
O
2
? F eO + SO
2
 
 
Q2:  In the extraction of copper from its sulphide ore, the metal is formed by reduction of ????
?? ?? 
with 
(A) ?????? 
(B) ? ?? 
(C) ????
?? ?? 
(D) ????
?? 
Ans: (C) Cu can be reduced by self-reduction. So, 
Cu
2
 S +
3
2
O
2
? Cu
2
O + SO
2
; 2 Cu
2
O + Cu
2
 S ? 6C u + SO
2
 
 
Q3:  Pyrolusite is a/an 
(A) Oxide ore 
(B) Sulphide ore 
(C) Carbide ore 
(D) Not an ore 
Ans:  (A) Pyrolusite ? Mn O
2
 
 
Q4: The metal always found in the free state is 
(A) ???? 
(B) ???? 
(C) ???? 
(D) ???? 
Ans:  (A) Ag, Au, Hg, Pt are chemically inert metals. 
 
 
Q. 5 In the extraction of iron, the slag produced is? 
(A) ???? 
(B) ?????????? ?? 
(C) ?????? ???? ?? 
(D) ???? ?? ???? ?? 
Ans: (D) Ca O
 lime 
+ SiO
2
 silica 
? Ca S i O
3
 slag 
 
 
 
Q6: Which alloy of aluminium is used in aircraft industry 
(A) Duralumin 
(B) Magnalium 
(C) Nickeloy 
(D) alunico 
Ans: (A) Duralumin an alloy of aluminium is used in aircraft industry 
 
Q7:  The common impurities present in the bauxite ore are 
(A) ????
?? ?? ?? and ???? ?? 
(B) ????
?? ?? ?? and ?????? 
(C) ????
?? ?? ?? and ?? ???? ?? 
(D) ?? ???? ?? and ???? ?? 
Ans: (C) Bauxite ore impurities: - SiO
2
+ Fe
2
O
3
 
Acidic impuntities 
 
Q8:  The material used in solar cell contains 
(A) ???? 
(B) ???? 
(C) ???? 
(D) Cs 
Ans:  (A) Si is a semi-conductor. 
 
Q9:  Cyanide process is used for the extraction of: 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ???? 
Ans: (A) 
 
 
Q10:  During smelting, an additional substance is added which combines with impurities to form a 
fusible product. It is known as 
(A) Slag 
(B) Mud 
(C) Gangue 
(D) Flux 
Ans: (D) Flux + Gangue ? slag. 
 
Q11:  Purification of silicon element used in semiconductors is done by 
(A) Zone refining 
(B) Heating 
(C) Froth floatation 
(D) Heating in vacuum 
Ans: (A) Zone refining: - Purification is done at microscopic level because we need ultra -purified 
element to use in semi-conductors. Zone refining is based on fractional crystallisation. 
 
Q12:  Aluminothermic process is used for metallurgy of 
(A) ???? 
(B) ???? 
(C) ???? 
(D) None of these 
Ans: (D) None of this elements can be reduced by Al but other example are Cr , Mn , Ti, etc. 
 
Q13:  In electrorefining of copper some gold is deposited as 
(A) Anode mud 
(B) Cathode mud 
(C) Cathode 
(D) Electrolyte 
Ans: (A) Anode mud are the elements which get deposited in the bottom of anode Eg. Ag, Au, Pt. 
 
Q14:  Poling process is used 
(A) For the removal of ????
?? ?? from ???? 
(B) For the removal of ????
?? ?? ?? from ???? 
(C) For the removal ????
?? ?? ?? from ???? 
(D) In all the above 
Ans: (A) Poling:- Molten metal is stirred with green anode poles which releases hydrocarbon (gas) 
which reduces the oxide e.g. Cu 
Cu
2
O + CO ? 2C u + CO
2
; Cu
2
O + H
2
? 2C u + H
2
O 
 
Q15:  Which of the following is not a basic flux? 
(A) ???? ???? ?? 
(B) ???? ?? 
(C) ?? ???? ?? 
(D) ?????? 
Ans: (C) S i O
2
 is an acidic flux SiO
2
 Acidic 
+ Ca O
 Bassic 
? Ca S i O
3
 
 
Q16:  Zone refining is a method to obtain 
(A) Very high temperature 
(B) Ultra pure ???? 
(C) Ultra pure metal 
(D) Ultra pure oxides 
Ans: (C) Zone refining is a method to obtain ultra pure metal. 
 
 
Q17:  Mac Arthur process is use for 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ?? ?? 
Ans: (A) Mac Arthur process is basically cyanide process. 
 
Q18:  Use of electrolysis is 
(A) Electroplating 
(B) Electrorefining 
(C) Both (A) and (B) 
(D) None of these 
Ans: (C) Electroplating: To deposit a specific metal on some other to protect the inner ore is done by 
electrolysis. 
Electrorefining: Electrochemical series decide which metal to be deposited first on anode and using 
it, we can remove the impurities by electro lysis. 
 
 
 
 
 
Page 5


JEE Solved Example on General Principles and 
Processes of Isolation of Metals 
Q1:  In presence of oxygen, removal of sulphur from an ore is included in 
(A) Calcination 
(B) Roasting 
(C) Smelting 
(D) Fluxing 
Ans:  (B) During roasting, air is blown to convert metal sulphides into metal oxides. 
F eS +
3
2
O
2
? F eO + SO
2
 
 
Q2:  In the extraction of copper from its sulphide ore, the metal is formed by reduction of ????
?? ?? 
with 
(A) ?????? 
(B) ? ?? 
(C) ????
?? ?? 
(D) ????
?? 
Ans: (C) Cu can be reduced by self-reduction. So, 
Cu
2
 S +
3
2
O
2
? Cu
2
O + SO
2
; 2 Cu
2
O + Cu
2
 S ? 6C u + SO
2
 
 
Q3:  Pyrolusite is a/an 
(A) Oxide ore 
(B) Sulphide ore 
(C) Carbide ore 
(D) Not an ore 
Ans:  (A) Pyrolusite ? Mn O
2
 
 
Q4: The metal always found in the free state is 
(A) ???? 
(B) ???? 
(C) ???? 
(D) ???? 
Ans:  (A) Ag, Au, Hg, Pt are chemically inert metals. 
 
 
Q. 5 In the extraction of iron, the slag produced is? 
(A) ???? 
(B) ?????????? ?? 
(C) ?????? ???? ?? 
(D) ???? ?? ???? ?? 
Ans: (D) Ca O
 lime 
+ SiO
2
 silica 
? Ca S i O
3
 slag 
 
 
 
Q6: Which alloy of aluminium is used in aircraft industry 
(A) Duralumin 
(B) Magnalium 
(C) Nickeloy 
(D) alunico 
Ans: (A) Duralumin an alloy of aluminium is used in aircraft industry 
 
Q7:  The common impurities present in the bauxite ore are 
(A) ????
?? ?? ?? and ???? ?? 
(B) ????
?? ?? ?? and ?????? 
(C) ????
?? ?? ?? and ?? ???? ?? 
(D) ?? ???? ?? and ???? ?? 
Ans: (C) Bauxite ore impurities: - SiO
2
+ Fe
2
O
3
 
Acidic impuntities 
 
Q8:  The material used in solar cell contains 
(A) ???? 
(B) ???? 
(C) ???? 
(D) Cs 
Ans:  (A) Si is a semi-conductor. 
 
Q9:  Cyanide process is used for the extraction of: 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ???? 
Ans: (A) 
 
 
Q10:  During smelting, an additional substance is added which combines with impurities to form a 
fusible product. It is known as 
(A) Slag 
(B) Mud 
(C) Gangue 
(D) Flux 
Ans: (D) Flux + Gangue ? slag. 
 
Q11:  Purification of silicon element used in semiconductors is done by 
(A) Zone refining 
(B) Heating 
(C) Froth floatation 
(D) Heating in vacuum 
Ans: (A) Zone refining: - Purification is done at microscopic level because we need ultra -purified 
element to use in semi-conductors. Zone refining is based on fractional crystallisation. 
 
Q12:  Aluminothermic process is used for metallurgy of 
(A) ???? 
(B) ???? 
(C) ???? 
(D) None of these 
Ans: (D) None of this elements can be reduced by Al but other example are Cr , Mn , Ti, etc. 
 
Q13:  In electrorefining of copper some gold is deposited as 
(A) Anode mud 
(B) Cathode mud 
(C) Cathode 
(D) Electrolyte 
Ans: (A) Anode mud are the elements which get deposited in the bottom of anode Eg. Ag, Au, Pt. 
 
Q14:  Poling process is used 
(A) For the removal of ????
?? ?? from ???? 
(B) For the removal of ????
?? ?? ?? from ???? 
(C) For the removal ????
?? ?? ?? from ???? 
(D) In all the above 
Ans: (A) Poling:- Molten metal is stirred with green anode poles which releases hydrocarbon (gas) 
which reduces the oxide e.g. Cu 
Cu
2
O + CO ? 2C u + CO
2
; Cu
2
O + H
2
? 2C u + H
2
O 
 
Q15:  Which of the following is not a basic flux? 
(A) ???? ???? ?? 
(B) ???? ?? 
(C) ?? ???? ?? 
(D) ?????? 
Ans: (C) S i O
2
 is an acidic flux SiO
2
 Acidic 
+ Ca O
 Bassic 
? Ca S i O
3
 
 
Q16:  Zone refining is a method to obtain 
(A) Very high temperature 
(B) Ultra pure ???? 
(C) Ultra pure metal 
(D) Ultra pure oxides 
Ans: (C) Zone refining is a method to obtain ultra pure metal. 
 
 
Q17:  Mac Arthur process is use for 
(A) Ag 
(B) ???? 
(C) ???? 
(D) ?? ?? 
Ans: (A) Mac Arthur process is basically cyanide process. 
 
Q18:  Use of electrolysis is 
(A) Electroplating 
(B) Electrorefining 
(C) Both (A) and (B) 
(D) None of these 
Ans: (C) Electroplating: To deposit a specific metal on some other to protect the inner ore is done by 
electrolysis. 
Electrorefining: Electrochemical series decide which metal to be deposited first on anode and using 
it, we can remove the impurities by electro lysis. 
 
 
 
 
 
Q19:  Calcination is used in metallurgy for removal of 
(A) Water and sulphide 
(B) Water and ????
?? 
(C) ????
?? and ?? ?? ?? 
(D) ?? ?? ?? and ?? ?? ?? 
Ans: (B) Calcination: Ore is heated at high temperature in the absence of air. 
E.g. Applied for carbonate and hydrated ores. 
C uC O
3
· Cu ( OH )
2
? C uO + CO
2
+ H
2
O 
 
Q20:  In blast furnace, maximum temperature is in 
(A) Zone of fusion 
(B) Zone of combustion 
(C) Zone of slag combustion 
(D) Zone of reduction 
Ans: (B) 
 
Q21:  Of the following which cannot be obtained by electrolysis of the aqueous solution of their 
salts? 
(A) ???? 
(B) ???? and ???? 
(C) ???? 
(D) ???? 
Ans: (B) Mg and Al's aqueous solution on electrolysing gives hydrogen at anode. 
? Molten mixture is used.