Question

In which of the following reactions $H_2{O}_2$ acts as a reducing agent?
(a) $H_2{O}_2+2H^{+}+2e\to 2H_{2}O$
(b) $H_2{O}_2-2e\to O_2+2H^{+}$
(c) $H_2{O}_2+2e\to 2\left(O{H}^{-}\right)$
(d) $H_2{O}_2+2O{H}^{-}-2e\to O_2+2H_{2}O$

• A. (a), (c)
• B. (b), (d)
• C. (a), (b)
• D. (c), (d)

Answer 1

The correct option is B (b), (d)

In the reactions (b) and (d), $H_2{O}_2$ is oxidized and acts as reducing agent.
In the reactions (a) and (c), $H_2{O}_2$ is reduced and acts as oxidizing agent.
(a) $H_2{O}_2+2H^{+}+2e\to 2H_{2}O$ A molecule of $H_2{O}_2$ loses an O atom and is reduced.
(b) $H_2{O}_2-2e\to O_2+2H^{+}$ A molecule of $H_2{O}_2$ loses 2 electrons and is oxidized.
(c) $H_2{O}_2+2e\to 2\left(O{H}^{-}\right)$ A molecule of $H_2{O}_2$ gains 2 electrons and is reduced.
(d) $H_2{O}_2+2O{H}^{-}-2e\to O_2+2H_{2}O$ A molecule of $H_2{O}_2$ loses hydrogen and is oxidized.