(a) Sulphide ore is roasted to the oxide before reduction because metal oxides can be reduced to Non - metal by carbon and hydrogen much more easily than sulphides.(b) Sulphide ore is roasted to the oxide before reduction because metal oxides can be reduced to metal by carbon and hydrogen much more easily than sulphides. (c)Sulphide ore is roasted to the oxide before reduction because metal oxides can be reduced to metal by Oxygen much more easily than sulphides. (d) Sulphide ore is roasted to the oxide before reduction because metal oxides can be reduced to metal by hydrogen much more easily than sulphides.