• # question_answer 4) Justify that the reaction : $2C{{u}_{2}}O(s)+C{{u}_{2}}S(s)\to 6Cu(s)+S{{O}_{2}}(g)$ is a redox reaction. Identify the species oxidised/reduced, which acts as an oxidant and which acts as a reductant.

Oxidation state of each elements are assigned in the given reaction as $\overset{+1-2}{\mathop{2C{{u}_{2}}O(s)}}\,+\overset{+1-2}{\mathop{C{{u}_{2}}S(s)}}\,\to \overset{0}{\mathop{6Cu(s)}}\,+\overset{+4-2}{\mathop{S{{O}_{2}}}}\,$ Copper is reduced from (+1) state to zero state while sulphur is oxidised from (-2) state to (+4) state. Thus, the given reaction is a redox reaction. In the given reaction, $C{{u}^{+1}}$ acts as oxidant because itself it is reduced while sulphur $({{S}^{2-}})$ acts as reductant because it is itself oxidised to (+ 4) state.