Write balanced chemical equation for the reactions taking place when
(i) Zinc carbonate is calcinated.
(ii) Zinc sulphide is roasted or heated in air.
(iii) Zinc oxide is reduced to zinc.

Explanation

(i) `ZnCO_(3)(s)overset("heat")rarrZnO(s) + CO_(2)(g)` (Calcination)
(ii) `2ZnS(s) + 3O_(2)(g) overset("heat")rarr2ZnO(s) + 2SO_(2)(g)` (Roasting)
(iii) `ZnO(s) + C(s) overset("heat")rarr Zn(s) + CO(g)` (Reduction)