Question

Which of the following acts both as oxidising as well as reducing agent?

• A. $HN{O}_2$
• B. $H_2{O}_2$
• C. $H_{2}S$
• D. $S{O}_2$

Answer 1

The correct option is C $H_{2}S$

In $HN{O}_2$, the oxidation state of nitrogen is +4. So, nitrogen can get oxidized as well as reduced. Therefore, it acts both as an oxidizing and reducing agent.

The oxidation state of sulfur in $H_{2}S$ is -2 whereas in case of $S{O}_2$ it is +4. The minimum and maximum oxidation state of sulfur are -2 and +6. Thus, for $H_{2}S$ it can only reduce or donate electron whereas in case of sulfur dioxide it can change its oxidation number either from +4 to -2 (reduction) and +4 to +6 (oxidation).

So, the correct option is $C$