Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?

• Carbon and hydrogen are suitable reducing agent for metal sulphides

• The Δ_fG^o of the sulphide is greater than those for CS₂ and H₂S

• The Δ_fG^o  is negative for roasting of sulphide ore to oxide

• Roasting of the sulphide to the oxide is thermodynamically feasible

Titanium is a metal of modern times. It is obtained as oxide. Why it could not be extracted earlier despite its wide occurence?

Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present?

What criterion is followed for the selection of the stationary phase in chromatography?

What is the role of cryolite in the metallurgy of aluminium?

Why is zinc not extracted from zinc oxide through reduction using CO?

What is the role of graphite rod in the electrometallurgy of aluminium?

Predict conditions under which Al might be expected to reduce MgO.