NEET2007ChemistryGeneral Principles and Processes of Isolation of MetalsActual
Which of the following statement, about the advantage of roasting of sulphide ore before reduction is not true?
Options
- AThe G _f^ o of the sulphide is greater than those for CS ₂ and H ₂ ~S .
- BThe G _f^0 is negative for roasting of sulphide ore to oxide
- CRoasting of the sulphide to the oxide is thermodynamically feasible
- DCarbon and hydrogen are suitable reducing agents for metal sulphides
Correct answer
A. The G _f^ o of the sulphide is greater than those for CS ₂ and H ₂ ~S .
Step-by-step solution
The sulphide ore is roasted to oxide before reduction because the G of most of the sulphides are greater than those of CS ₂ and H ₂ ~S , 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.