Explain, why?
(a) $H_{2} S$ acts as reductant whereas, ${S O}_{2}$ acts as reductant and oxidant both.
(b) $H_{2} O_{2}$ acts as reductant and oxidant both.

Open in App

Solution

(a)
In $H_{2} S$ $S$ is in its lowest oxidation state that is $- 2$ . Hence, it can only act as a reducing agent only.

In $S O_{2}$ $S$ is in oxidation state that is $+ 4$ and its highest oxidation state is $+ 6$ . Hence, can act both as reducing agent and oxidising agent.

(b) Hydrogen peroxide acts as both a reducing and an oxidizing agent.
$1.$ When $H_{2} O_{2}$ serves as an oxidizing agent, the oxygen of hydrogen peroxide (that is present in $- 1$ oxidation state) is reduced to $H_{2} O$ ( $- 2$ oxidation state).

$H_{2} O_{2} + 2 H^{+} + 2 e^{-} \to 2 H_{2} O$
$2.$ When H2O2 (-1 oxidation state)serves as areducing agent, the oxygen of $H_{2} O_{2}$ is oxidized to $O_{2}$ ( 0 oxidation state) and bubbles are noticed. As a reducing agent:
$K M n O_{4} + 5 H_{2} O_{2} + 3 H_{2} S O_{4} \to K_{2} S O_{4} + 5 O_{2} + 2 M n S O_{4} + 8 H_{2} O$
or
$M n O_{4}^{-} + 5 H_{2} O_{2} + 6 H^{+} \to 5 O_{2} + 2 M n_{2} - + 8 H_{2} O$

Suggest Corrections

Similar questions

S O_{2}

H N O_{2}

H N O_{3}

H2O2 acts as a reductant as well as oxidant. Explain.

Join BYJU'S Learning Program