Oxidation and reduction always occur simultaneously. These reactions which involve simultaneous oxidation and reduction are called redox reactions. Therefore, every redox reaction is made up of two half reactions. One half reaction represents oxidation and other half reaction represents the reduction. Oxidation and reduction of an atom, molecule or ion can also be defined in terms of electrons. The substance that gains electrons, is reduced to a lower oxidation state and acts as an oxidising agent. Similarly, the substance which loses electrons is oxidised to a higher oxidation state, and is called a reducing agent.
In which of the following reactions hydrogen peroxide is acting as a reducing agent?

Options

A. `2FeCl_(2)+2HCl+H_(2)O_(2)to2FeCl_(3)+2H_(2)O`
B. `Cl_(2)+H_(2)O_(2)to2HCl+O_(2)`
C. `2HI+H_(2)O_(2)to2H_(2)O+I_(2)`
D. `H_(2)SO_(3)+H_(2)O_(2)toH_(2)SO_(4)+H_(2)O`

Answer

B

Explanation

`H_(2)O_(2)` is oxidised to `O_(2)`, hence acts as a reducing agent.