Hydrogen peroxide acts both as an oxidizing and as a reducing agent depending upon the nature of the reacting species. In which of the following cases `H_2O_2` acts as a reducing agent in acid medium?

Options

A. `MnO_(4)^(-)`
B. `Cr_(2)O_(7)^(2-)`
C. `SO_(3)^(2-)`
D. KI

Answer

A

Explanation

` 2 MnO_(4)^(-) + 6H^(+) + 5H_(2) O_(2) rarr 2 Mn^(2+) + SO_(2)+ 8H_(2)O`
In this reaction `KMnO_(4)` , is reduced from +7 to +2 oxidation state. Thus, it acts an oxidizing agent and `H_(2),O_(2)` , act as a reducing agent in acidic medium.