Question

Hydrogen peroxide acts both as an oxidising and as a reducing agent, depending upon the nature of the reacting species. In which of the following cases $H_2{O}_2$ acts as a reducing agent in acid medium?

• A. $Mn{O}_4^{-}$
• B. $C{r}_2{O}_7^{2-}$
• C. $S{O}_3^{2-}$
• D. $KI$

Answer 1

The correct option is A $Mn{O}_4^{-}$

The oxidation state of $Mn$ in $Mn{O}_4^{-}$ is $+7$. $H_2{O}_2$ can only reduce $Mn$ as it is in maximum oxidation state in $Mn{O}_4^{-}$.