Justify that the following reactions are redox reactions :
`CuO(s)+H_(2)(g)toCu(s)+H_(2)O(g)`

Explanation

`overset(+2)(cu) overset(-2)(O) (s) + overset(0)(H_(2)) (g) rarr overset(0)(Cu)(s) + overset(+1)(H_(2)) overset(-2)(O) (g)`
In this reaction, the oxidation state of Cu is decreasing from +2 (in CuO) to 0 (in Cu), hence, CuO is undergoing reduction. While the oxidation number of hydrogen is increasing from 0 (in `H_(2)`) to +1 (in `H_(2)O`), hence `H_(2)` is undergoing oxidation. Thereofre, it is a redox reaction.