Question

Which compound acts as an oxidising as well as reducing agent.

• A. $SO_{2}$
• B. $MnO_{2}$
• C. $Al_{2}O_{3}$
• D. $CrO_{3}$

Answer 1

Answer: (A)

$SO_{2}$

Answer 2

The minimum and maximum oxidation number of S are –2 and +6 respectively. Since the oxidation number of S in $SO_{2}$ is +4, therefore it can be either increased or decreased. Therefore $SO_{2}$ behaves both as an oxidising as well as reducing agent.