Question

In which of the following reactions, sulphur dioxide is not behaving as a reducing agent?

• A. $H_{2}O+S{O}_2\to H_{2}S{O}_3$
• B. $2H_{2}S+S{O}_2\to 3S+2H_{2}O$
• C. $K_{2}C{r}_2{O}_7+H_{2}S{O}_4+3S{O}_2\to K_{2}S{O}_4+C{r}_2(S{O}_4{)}_3+H_{2}O$
• D. Both (a) and (b)

Answer 1

The correct option is D Both (a) and (b)

In reaction (a), $S{O}_2$ is not reducing.
In reaction (b), $S{O}_2$ is reduced to $S$ and behaves as an oxidising agent.
In reaction (c), $S{O}_2$ is oxidised to $S{O}_4^{2-}$ and behaves as a reducing agent.