Q.1 Which of the following metals is obtained by electrolytic reduction from its ore?
Iron
Aluminium
Zinc
Copper
Explanation - Aluminium is extracted from bauxite by electrolytic reduction using molten cryolite as a solvent.
Correct answer is: Aluminium
Q.2 Which process is used to purify crude copper?
Electrorefining
Roasting
Calcination
Distillation
Explanation - Electrorefining involves using an electrolytic cell to remove impurities from impure copper, producing high-purity copper.
Correct answer is: Electrorefining
Q.3 Which of the following metals is obtained by self-reduction?
Iron
Copper
Mercury
Aluminium
Explanation - Copper is obtained from its sulfide ores by roasting to oxide followed by reduction with copper itself acting as the reducing agent (self-reduction).
Correct answer is: Copper
Q.4 Froth flotation is mainly used for the concentration of which type of ores?
Oxide ores
Sulfide ores
Carbonate ores
Native ores
Explanation - Froth flotation is a method used for concentrating sulfide ores by making them hydrophobic and separating them from gangue.
Correct answer is: Sulfide ores
Q.5 Which of the following is an example of a metallurgical flux?
SiO2
NaCl
K2SO4
CaCO3
Explanation - SiO2 acts as a flux in metallurgy to combine with impurities like basic oxides to form slag.
Correct answer is: SiO2
Q.6 Which metal is extracted by carbon reduction at high temperature?
Sodium
Iron
Aluminium
Potassium
Explanation - Iron is extracted from hematite by reduction with carbon (coke) in a blast furnace at high temperature.
Correct answer is: Iron
Q.7 Which ore is concentrated by the process of magnetic separation?
Haematite
Magnetite
Bauxite
Galena
Explanation - Magnetite is a magnetic iron ore, and magnetic separation is used to separate it from non-magnetic gangue.
Correct answer is: Magnetite
Q.8 The principle of hydrometallurgy is based on:
Solubility of metal compounds
High temperature reduction
Electrolysis of molten salts
Roasting of ores
Explanation - Hydrometallurgy involves leaching ores with aqueous solutions based on the solubility differences of metal compounds.
Correct answer is: Solubility of metal compounds
Q.9 Which method is commonly used to extract gold from its ore?
Amalgamation
Electrolysis
Calcination
Froth flotation
Explanation - Gold is extracted from low-grade ores using mercury to form an amalgam, which is later heated to recover gold.
Correct answer is: Amalgamation
Q.10 Which of the following metals is obtained by the Mond process?
Nickel
Copper
Zinc
Iron
Explanation - The Mond process purifies nickel by forming volatile nickel carbonyl (Ni(CO)4), which decomposes to give pure nickel.
Correct answer is: Nickel
Q.11 Which of the following is used as a reducing agent in the extraction of aluminium?
Carbon
Electrolysis
Hydrogen
Sodium
Explanation - Aluminium is highly reactive and is extracted from alumina by electrolysis of molten cryolite; chemical reducing agents like carbon are ineffective.
Correct answer is: Electrolysis
Q.12 Which step in metallurgy involves the removal of gangue from ore?
Concentration
Roasting
Calcination
Smelting
Explanation - Concentration or dressing of ore removes impurities (gangue) from the ore to increase the metal content before extraction.
Correct answer is: Concentration
Q.13 Which process is used for the purification of zinc?
Distillation
Electrorefining
Liquation
Froth flotation
Explanation - Zinc has a low boiling point and is purified by distillation after reduction from its ore.
Correct answer is: Distillation
Q.14 Which of the following metals is extracted from its oxide ore by reduction with CO?
Iron
Copper
Mercury
Aluminium
Explanation - Iron oxide (Fe2O3) is reduced to iron in a blast furnace using carbon monoxide as the reducing agent.
Correct answer is: Iron
Q.15 Which method is suitable for the extraction of highly reactive metals like potassium?
Electrolysis of molten salts
Carbon reduction
Hydrogen reduction
Smelting
Explanation - Highly reactive metals like potassium cannot be extracted by carbon; they require electrolysis of their molten salts.
Correct answer is: Electrolysis of molten salts
Q.16 Which of the following ores is purified by the process of calcination?
Bauxite
Galena
Pyrite
Magnetite
Explanation - Calcination involves heating the ore in the absence of air to remove moisture or volatile impurities, e.g., bauxite.
Correct answer is: Bauxite
Q.17 Which of the following metals can be obtained by roasting its sulfide ore?
Copper
Sodium
Potassium
Aluminium
Explanation - Copper sulfide ores are roasted in air to convert them into copper oxide, which can then be reduced to copper metal.
Correct answer is: Copper
Q.18 Which of the following is a metallurgical operation that involves heating ore below its melting point?
Calcination
Smelting
Electrolysis
Distillation
Explanation - Calcination is heating of ores below their melting point to remove moisture or volatile impurities.
Correct answer is: Calcination
Q.19 Which method is used for the extraction of silver from argentite (Ag2S)?
Cupellation
Amalgamation
Electrolysis
Distillation
Explanation - Silver is extracted from argentite by cupellation, which separates silver from lead by oxidation.
Correct answer is: Cupellation
Q.20 Which of the following processes involves heating ore in the presence of air?
Roasting
Calcination
Smelting
Electrolysis
Explanation - Roasting involves heating sulfide ores in air to convert them into oxides, releasing sulfur dioxide.
Correct answer is: Roasting
Q.21 Which process is used to separate a metal from its alloy in pure form?
Liquation
Calcination
Roasting
Electrolysis
Explanation - Liquation involves heating a low-melting-point metal alloy to separate the more fusible metal from the higher melting point metal.
Correct answer is: Liquation
Q.22 Which of the following metals is obtained from its carbonate ore by thermal decomposition?
Calcium
Iron
Copper
Sodium
Explanation - Calcium carbonate decomposes on heating to form calcium oxide, which can then be reduced to calcium metal.
Correct answer is: Calcium
Q.23 Which of the following methods is used to concentrate bauxite ore?
Hydraulic washing
Magnetic separation
Froth flotation
Leaching with NaOH
Explanation - Bauxite is concentrated by treating with NaOH, which dissolves aluminium hydroxide, leaving impurities behind.
Correct answer is: Leaching with NaOH
Q.24 Which metal is obtained by the electrolytic refining of an impure metal using an acidic solution?
Copper
Aluminium
Zinc
Iron
Explanation - Impure copper acts as the anode and pure copper plates out at the cathode during electrolytic refining in acidic solution.
Correct answer is: Copper
Q.25 Which step in metallurgy involves converting metal oxides into free metal?
Reduction
Roasting
Concentration
Calcination
Explanation - Reduction is the chemical process where metal oxides are converted into pure metals by removing oxygen.
Correct answer is: Reduction