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

`2 overset(+1)(Cu), overset(-2)O_((s))+overset(+1)(Cu). overset(-2)(S_(s)) to 6 overset(0)(Cu_((s)) + overset(+4)(S) overset(-2)(O)`,
In this reaction copper is reduced from +1 state to zero oxidation state and sulphur is oxidised form -2 state to +$ state. The above reaction is thus a redox reaction.
Further, `Cu_(2)O` 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.