Question

An acidic solution of hydrogen peroxide behaves as an oxidising as well as reducing agent. Illustrate it with the help of a chemical equation.

Answer 1

Oxidising action of hydrogen peroxide $\left(H_2{O}_2\right)$ in acidic medium:

$2I^{-}+2H^{+}+H_2{O}_2\to I_2+2H_{2}O$
$I=-1$ $H=+1$ $H=+1$ $I=0$ $H=+1$

$O=-1$ $O=-2$

Therefore,

$2I^{-}+2H^{+}+H_2{O}_2\to I_2+2H_{2}O$

In this reaction, $H_2{O}_2$ is oxidising $I^{-}$ to $I_2$ and itself getting reduced to $H_{2}O.$

Thus, the acidic solution of $H_2{O}_2$ is acting as an oxidising agent.

Reducing action of hydrogen peroxide $\left(H_2{O}_2\right)$ in acidic medium:

$2Mn{O}_4^{-}+6H^{+}+5H_2{O}_2$

$\downarrow$

$2M{n}^{2+}+8H_{2}O+5O_2$

In this reaction, $Mn{O}_4^{-}$ is getting reduced to $M{n}^{2+}$ as oxidation number is getting reduced from $+7$ to $+2,$ while $H_2{O}_2$ is getting oxidised to $O_2.$

Thus, the acidic solution of $H_2{O}_2$ is acting as a reducing agent.