Question

Roasting results in the formation of oxides. But why are oxide ores are subjected to roasting?

(a) To avoid gangue particles

(b) To get crude metal with using oxidizing agent

(c) To remove volatile impurities in the form of their oxides

(d) To make the ore porous

I got this question in examination.

The origin of the question is Extraction of Crude Metal from Concentrated Ore in division General Principles and Processes of Isolation of Elements of Chemistry – Class 12

Answer 1

Right answer is (c) To remove volatile impurities in the form of their oxides

Explanation: Oxide ores are subjected to roasting to remove the volatile impurities in the form of their oxides. It is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides. So before reduction can be done, the ore is converted into metal oxide.