13. Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true? (2007)
(a) The ΔGf° of the sulphide is greater than those for CS2 and H2S.
(b) The ΔGf° is negative for roasting of sulphide ore to oxide.
(c) Roasting of the sulphide to the oxide is thermodynamically feasible.
(d) Carbon and hydrogen are suitable reducing agents for metal sulphides.