Write chemical reactions to justifty that hydrogen peroxide can function as an oxidising as well as reducing agent.

Explanation

Hydrogen peroxide behaves both as an oxidising agent as well as reducing agent both in acidic and alkaline medium. The oxidation state of O in `H_2O_2` is -1. Therefore, it can be oxidised to `O_2` (zero oxidation state) or reduced to `H_2 O_2` or `OH^(-)`(-2 oxidation state). Some reactions of `H_2O_2` are
(i) Oxidising action in acidic medium.
`2Fe^(2+)(aq) + H_2 O_2 (aq) + 2H^(+) (aq) to 2Fe^(3+) (aq) + 2H_2 O`
(ii) Oxidising action in basic medium.
`Mn^(2+)(aq) + H_2 O_2 (aq) + 2OH^(-) to MnO_2 (s) + 2H_2 O(l)`
(iii) Reducing action in acidic medium
`2MnO_4^(-) + 6H^(+) (aq) + 5H_2 O_2 (aq) to 2Mn^(2+) (aq) + 8H_2 O(l) + 5O_2(g)`
(iv) Reducing action in basic medium
`2Fe^(3+) (aq) + H_2 O_2 (aq) + 2OH^(-)(aq) to 2Fe^(2+) (aq) + O_2 (g) + 2H_2 O_2 (l)`