Metallurgy

Step 1:
- Siderite is a mineral that primarily contains iron carbonate ( ). Thus, it corresponds to composition III.
Step 2:
- Malachite is a copper carbonate mineral ( ). Hence, it matches with V.
Step 3:
- Sphalerite is a zinc sulfide mineral ( ). Therefore, it corresponds to I.
Step 4:
- Zincite is an ore of zinc and contains zinc oxide ( ). Therefore, it matches with II. Thus, the correct matching is:

Step 1: Analyze each process:

• (A) Hall-Heroult process: Used for the extraction of Aluminium. It involves the electrolysis of fused mixture of alumina ( ) and cryolite ( ). This fits the description.
• (B) Van Arkel method: Used for refining Zirconium (Zr) or Titanium (Ti). It is a vapour phase refining process (formation and decomposition of iodide). No electrolysis.
• (C) Mond process: Used for refining Nickel (Ni). It involves the formation of volatile nickel tetracarbonyl and its subsequent thermal decomposition. No electrolysis.
• (D) Solvay process: Used for the manufacture of Sodium Carbonate ( ). It involves chemical precipitation reactions (using brine, ammonia, ). No electrolysis.

Step 2: Conclusion:
Only the Hall-Heroult process uses electrolysis.

Copper is refined by electrolytic refining, not vapor phase refining. Zinc by distillation, tin by liquation, and indium by zone refining are correct.

1. (1) Siderite: FeCO , correct (iron carbonate ore).
2. (2) Malachite: Cu (OH) CO , not Cu S (chalcocite), incorrect.
3. (3) Calamine: ZnCO , correct (zinc carbonate ore).
4. (4) Fools gold: FeS (pyrite), correct.
5. Thus, the incorrect match is (2) Malachite - Cu S.