Question

How are the oxides of less reactive metals like silver and mercury reduced?

(a) By thermal decomposition

(b) By electrolysis

(c) By using reducing agents

(d) Cannot be reduced

I have been asked this question in an internship interview.

My question comes from Thermodynamic Principles of Metallurgy topic in portion General Principles and Processes of Isolation of Elements of Chemistry – Class 12

Answer 1

Correct choice is (a) By thermal decomposition

To explain I would say: In case of less reactive metals like silver and mercury, ΔfG° becomes positive at higher temperatures. This suggests that both silver oxide (Ag2O) and mercury oxide (HgO) are unstable and hence decompose at high temperatures to liberate the corresponding metal.