Chemistry - Metallurgy Question with Solution | TestHub

Option C is correct because sulfide ions (S²⁻) act as reducing agents in the extraction of Cu, Pb, and Hg from their sulfide ores. For example, in copper extraction, Cu₂S reacts with O₂ to form Cu and SO₂.

Option D is correct because cupellation is an oxidation method used to refine noble metals like silver and gold, separating them from base metals by selective oxidation.

Explanation for incorrect options:

A. Ignition mixture for thermite reaction involves Al powder and Fe₂O₃, not BaO₂.

B. Beneficiation by chemical method (leaching) is used for ores like gold, silver, and bauxite, not typically for copper pyrite (which uses froth flotation).