Hydrogen peroxide can function as an oxidising agent as well as reducing agent. Substantiate statement with suitable examples.

Explanation

Hydrogen peroxide acts as an oxidising agent as well as a reducing agent. Oxidation usual performed in acidic medium while reduction reactions are performed in alkaline medium. Eg `:` In acidic medium.
(i) `H_(2) O_(2) ` oxidises nitrites to nitrates.
`H_(2) O_(2) rarr H_(2) O^(+) [O]`
`NaNO_(2) + [O] rarr NaNO_(3)`
`bar( NaNO_(2) + H_(2) O_(2) rarrNaNO_(3) + H_(2) O)`
(ii) `H_(2) O_(2)` oxidises `Cr(OH)_(3)` to yellow sodium chromate in basic medium.
`3( H_(2) O_(2)) rarr H_(2) O + O`
`2Cr( OH )_(3) + 4NaOH + 3O rarr 2Na_(2) CrO_(4) + 5H_(2) O`
`bar( 2Cr(OH)_(5) + 4NaOH + 3H_(2) O_(2) rarr 2Na_(2) O_(2) rarr 2Na_(2) CrO_(4) + 8 H_(2) O )`
Reducing agent `:`
(i) It reduces acidified `KMnO_(4)` to `Mn^(+2)`
`2KMnO_(4) + 3H_(2)SO_(4) + 5H_(2) O_(2) rarr K_(2) SO_(4) + 2MnSO_(4) + H_(2) O + 5O_(2)`
(ii) It reduces `Ag_(2) O` to `Ag ` `:`
`Ag_(2) O + H_(2) O_(2) rarr 2Ag + H_(2) + O_(2)`