Justify that the reaction
`2Cu_(2)O_(s)+Cu_(2)S(s)rarr6Cu(s)+SO_(2)(g)` a redox reaction. Identify the species oxidised`//`reduced. Which acts as an oxidanat and which acts as a reductant?

Explanation

Let us assign oxidation number to each of the species in the reaction under examination . This results into :
`overset(+1)(2Cu_(2))overset(-2)(O)(s) + overset(+1)(Cu_(2))overset(-2)(S)(s) to 6 overset(0)(Cu)(s) + overset(+4)(S)overset(-2)(O_(2))`
We We therefore, conclude that 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)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.