Justify that the reaction : `2Cu_(2) O(s) + Cu_(2)S (s) rarr 6 Cu (s) + SO_(2) (g)` is a redox reaction. Identify the species oxidised/reduced, which acts as an oxidant and which acts as a reductant.

Explanation

`overset(+1)(2Cu_(2))overset(-2)(O_((s)))+overset(+1)(Cu_(2))overset(-2)(S_((s)))rarroverset(0)(6Cu_((s)))+overset(+4-2)(SO_(2))`
In this reaction copper is reduced from `+ 1` state to zero oxidation state and sulphur is oxidised from `- 2` state to `+ 4` state. The above reaction is thus a redox reaction.
Further, `Cu_(2)S` helps sulphur in `Cu_(2)S` to increase its oxidation number,therefore `Cu(I)` is an oxidant, and sulphur of `Cu_(2)S` helps copper both in `Cu_(2)S` itself and `Cu_(2)O` to decrease its oxidation number, therefore, sulphur of `Cu_(2)S` is reductant.