Same chapter3 marksDifficulty: Medium
Distinguish between calcination and roasting.
General Principles and Processes of Isolation of Elements
3 marksDifficulty: Medium
Name three methods of refining a crude metal and state where each is used.
Original Khojo Papers practice question — not from a past board paper.
Answer
Distillation is used for low-boiling metals such as zinc and mercury. Electrolytic refining is used for copper, silver, aluminium and lead. Zone refining is used for metals needed in very high purity, such as silicon and germanium, and vapour phase refining is used for nickel by the Mond process.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Zone refining works because impurities are more soluble in the molten than in the solid metal.
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