Purification And Characterisation Of Organic Compounds Question 156
Question: Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true-
Options:
A) The $ \Delta G _{f}^{{}^\circ } $ of the sulphide is greater than those for $ CS_2 $ and $ H_2s $ .
B) The $ \Delta G _{f}^{{}^\circ } $ 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 reduction of metal sulphides.
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Answer:
Correct Answer: D
Solution:
[d] The sulphide ore is roasted to oxide before reduction because the $ \Delta G _{f}^{{}^\circ } $ of most of the sulphides are greater than those of $ CS_2 $ and $ H_2S $ , therefore neither C nor H can reduce metal sulphide to metal.
Further, the standard free energies of formation of oxide are much less than those of $ SO_2.
$ Hence oxidation of metal sulphides to metal oxide is thermodynamically favourable.
BETA
