Question

Which of the following oxides can act both as an oxidising agent as well as reducing agent ?

• A. $N_{2}O$
• B. $S{O}_2$
• C. $S{O}_3$
• D. $P_2{O}_5$

Answer 1

Answer: (B)

$S{O}_2$ oxides can act both as an oxidising agent as well as reducing agent. It behaves as a reducing agent in moist conditions. It convert iron (III) ions to iron (II) ions and decolourises acidified potassium permanganate (VII) solution.

$2F{e}^{3+}+S{O}_2+2H_{2}O⟶2F{e}^{2+}+S{O}_4^{2-}+4H^{+}$

When $S{O}_2$ reacts with $H_{2}S$, it produces sulphur and water. In this reaction, '$S{O}_2$, act as an oxidising agent.