Question

Identify the oxidant and reductant in the reactions:

10H⁺(aq) + 4Zn(s) + NO₃^–(aq) → 4Zn²⁺(aq) + NH₄⁺ + 3H₂O(l)

Answer 1

Writing the O.N. of all the atoms above their symbols, we have

O.N. of Zn changes from zero in Zn to +2 in Zn²⁺ and, therefore, it is oxidized and hence Zn acts as a reductant.

The O.N. of N decreases from +5 in NO₃^– to -3 in NO₄⁺ and, therefore, it is reduced and hence NO₃^– acts as the oxidant.