The chemical reactions in the two caes may be expressed as :
`2CuS (s) +C(s) to CS_(2) (l) +2 Cu(s)`
`CuO+C(s) to CO(g)+ Cu (s)`
In the first case, carbon disulphide formed in the reaction is a liquid whereas carbon monoxide is in the gaseous state in the second case. Consequently, the reduction reaction is thermodynamically more feasible in the second case than in the first case.
