Hydrogen peroxide is a powerful oxidising agent, both in the acidic and alkaline medium.
In acidic medium: `H_(2)O_(2)+2H^(o+)+2e^(ɵ)to2H_(2)O`
In alkaline medium: `H_(2)O_(2)+2e^(ɵ)to2overset(Theta)(O)H`
Hydrogen peroxide acts as a reducing agent towards powerful oxidising agents.
In acidic medium: `H_(2)O_(2)to2H^(o+)+O_(2)+2e^(ɵ)` In alkaline medium, however, its reducing nature is more effective.
`H_(2)O_(2)to2H^(o+)+O_(2)+2e^(ɵ)`
In which of the following reactions, `H_2O_2` act as a reducing agent?

Options

A. `PbO_(2)+H_(2)O_(2)rarrPbO+H_(2)O+O_(2)`
B. `Na_(2)SO_(3)+H_(2)O_(2)rarrNa_(2)SO_(4)+H_(2)O`
C. `2KI+H_(2)O_(2)rarr2KOH+I_(2)`
D. `KNO_(2)+H_(2)O_(2)rarrKNO_(3)+H_(2)O`

Answer

A

Explanation

`overset(+4)(PbO_(2)) + H_(2)O_(2) rarr overset(2+)PbO+H_(2)O + O_(2)`