Hydrogen peroxide is now generally prepared on industrial scale by the

Options

A. action of `H_(2)SO_(4)` on barium peroxide
B. action of `H_(2)SO_(4)` on sodium perioxide
C. electrolysis of `50% H_(2)SO_(4)`
D. burning hydrogen in excess of oxygen

Answer

C

Explanation

Industrial preparation of `H_(2)O_(2):`
`(A)` By the electrolysis of `50%H_(2)SO_(4): 50% H_(2)SO_(4)` solution is electrolysed at `0^(@)C` between `Pt` electrodes. The perdisulphuric acid is formed.
`H_(2)SO_(4)hArr H^(+)+HCO^(-4)`
At Anode`:" "2HSO_(4)^(-)rarr H_(2)S_(2)O_(8)+2e`
At Cathode `:" "2H^(+)+2e rarr H_(2)`
The obtained perdisulphuric acid gives `H_(2)O_(2)` on hydrolysis.
`H_(2)S_(2)O_(8) hArr H_(2)O_(2)+2H_(2)SO_(4)`
This `H_(2)O_(2)` is separated by distillation at reduced pressure and thus, `30%` solution of `H_(2)O_(2)` is obtained.
`(B)` By the auto `-` oxidation of `2-`ethyl `-` anthraquinol `(` Modern method `)` : Anthraquinol, in a mixture of benzene and `n-` heptanol on treatment with air gives `H_(2)O_(2)` and `2-` ethyl`-` anthraquinone. This `2-` ethyl `-` anthraquinone on hydrogenation gives `2-` anthraquinol in presence of `Pd` catalyst.

It is a cyclic process and it only `H_(2)` is consumed, `2-` ethyl`-` anthraquinone is reobtained during reaction.