Chemistry - Metallurgy Question with Solution | TestHub

Bauxite is purified by leaching (Bayer’s process) to form alumina, but aluminum is not extracted by metal displacement.

Aluminum is obtained by electrolytic reduction of molten Al₂O₃ (Hall–Héroult process.

Other processes are correct: cinnabar gives Hg by roasting followed by decomposition, argentite by cyanide leaching and Zn displacement, and galena by roasting and carbon reduction.

Hence, option (D) is the incorrect process.