41. Which metal is extracted from its ore using the Mond process?
- A) Copper
- B) Iron
- C) Nickel
- D) Zinc
Answer: C) Nickel
Explanation: The Mond process is used to extract and purify nickel. In this process, nickel reacts with carbon monoxide to form nickel carbonyl, which decomposes to yield pure nickel.
42. During the roasting of pyrite (FeS2), the following gas is produced:
- A) Carbon dioxide
- B) Sulphur dioxide
- C) Hydrogen sulphide
- D) Oxygen
Answer: B) Sulphur dioxide
Explanation: During the roasting of pyrite, iron sulphide (FeS2) reacts with oxygen to produce sulphur dioxide (SO2) and iron oxide.
43. The process of leaching involves:
- A) Heating of ore in the presence of oxygen
- B) Heating the ore with reducing agent
- C) Treating the ore with suitable reagent to form a soluble compound
- D) Electrolytic reduction of ore
Answer: C) Treating the ore with suitable reagent to form a soluble compound
Explanation: Leaching is a hydrometallurgical process where the ore is treated with a reagent that dissolves the desired metal, forming a soluble compound, which can then be recovered.
44. Which of the following processes is used to extract metals from sulphide ores?
- A) Roasting
- B) Calcination
- C) Distillation
- D) Electrolysis
Answer: A) Roasting
Explanation: Roasting is used to extract metals from sulphide ores by heating them in the presence of air to convert the sulphides into oxides.
45. The impurities left behind after electrorefining of copper are known as:
- A) Anode mud
- B) Cathode deposit
- C) Slag
- D) Dross
Answer: A) Anode mud
Explanation: During the electrorefining of copper, impurities such as silver and gold settle at the bottom of the cell as anode mud.
46. Which of the following metals is extracted by the auto-reduction process?
- A) Zinc
- B) Copper
- C) Aluminium
- D) Iron
Answer: B) Copper
Explanation: Copper is extracted by auto-reduction (self-reduction), where Cu2S is converted to copper metal by reaction with oxygen. This occurs during the final stages of copper extraction in the Bessemer converter.
47. The electrochemical method used for refining copper is known as:
- A) Electroplating
- B) Electrolysis
- C) Electrorefining
- D) Electrowinning
Answer: C) Electrorefining
Explanation: Electrorefining is used for the purification of copper. Impure copper is made the anode, and pure copper is deposited at the cathode.
48. In the metallurgy of iron, the function of coke is to:
- A) Act as a reducing agent
- B) Act as an oxidizing agent
- C) Remove impurities
- D) Form slag
Answer: A) Act as a reducing agent
Explanation: Coke is used in the blast furnace as a reducing agent to convert iron oxides into iron metal.
49. During the extraction of copper, which step involves the use of SiO2?
- A) Smelting
- B) Electrorefining
- C) Roasting
- D) Reduction
Answer: A) Smelting
Explanation: During smelting, silica (SiO2) is added as a flux to remove iron impurities in the form of iron silicate (slag).
50. The metal obtained after smelting iron ore in the blast furnace is called:
- A) Pig iron
- B) Wrought iron
- C) Steel
- D) Cast iron
Answer: A) Pig iron
Explanation: Pig iron is the first product obtained from smelting iron ore in a blast furnace. It contains high carbon content and other impurities.
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