Question

A sulphide ore is generally roasted to the oxide before reduction, because -

• A. The enthalpy of formation of CO₂ is more than that of CS₂
• B. A metal sulphide is generally more stable than the metal oxide
• C. No reducing agent is found suitable for reducing a sulphide ore
• D. A sulphide ore cannot be reduced at all

Answer 1

Answer: (A)

The enthalpy of formation of CO₂ is more than that of CS₂

Answer 2

Carbon is usually used for the reduction of ores and if sulphide ores are used, it will form CS₂ which is difficult to remove. Therefore, sulphide ores are first roasted to metal oxides which are then reduced by carbon to give metal and CO escapes easily into the air.