MEDIUMMCQ SINGLEIChO (Chemistry Olympiad)Inorganic ChemistryMetallurgyPrevious Year Questions
Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true? (RPMT 2007)
A.The Gf° of the sulphide is greater than those for
B.The Gf° is negative for roasting of sulphide ore to
C.Roasting of the sulphide to the oxide is
D.Carbon and hydrogen are suitable reducing agents✓ Correct
Explanation
The standard free energies of formation (Gf°) of most of the sulphides are greater than those of CS₂ and H₂S. Hence, neither carbon nor hydrogen can reduce metal sulphides to metal. The standard free energies of formation of oxides are much lower than those of SO₂. Therefore, oxidation of metal sulphides to metal oxides is thermodynamically favourable. Hence, sulphide ore is roasted to the oxide before reduction. 10. Identify the reaction that does not take place in a blast furnance. (AIPMT 2008) (a) 2Fe₂O₃ + 3C → 4Fe + 3CO₂ (b) CO₂ + C → 2CO (c) CaCO₃ → CaO + CO₂ (d) FeO + SiO₂ → FeSiO₃
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