Justify that the following reactions are redox reactions:
CuO(s) + H2(g) → Cu(s) + H2O(g)
Let us write the oxidation number of each element involved in the given reaction as:
In CuO, Cu = + 2 and O = -2
In H2, H = 0
In H2O, H = + 1 and O = -2
In Cu, Cu = 0
Here, the oxidation number of Cu decreases from + 2 in CuO to 0 in Cu i.e., CuO is reduced to Cu. Also, the oxidation number of H increases from 0in H2 to + 1in H2O i.e.,H2is oxidised to H2O. Hence, this reaction is a redox reaction.