Assertion: Sulphide ores of `Zn`and `Pb` are generally converted into their respective oxides, prior to reduction.
Reason: The zinc oxide and lead oxide are reduced by carbon to their respective free metals.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer

A

Explanation

Assertion: The Gibbs energies of formation of most sulphide are greater than that for `CS_(2)`.In fact, `CS_(2)` is an endothermic compound. There, the `Delta_(f) G^(Theta)` of `M_(x) S` is not compensated. So reduction `M_(x)S` is difficult. Hence it is common practice to roast sulphide ores to corresponding oxides prior to reduction.
Reason: `ZnO+C overset(Delta) vrarr Zn +CO`,
`PbO+C overset(Delta)rarr Pb +CO` (carbon reuction)