Give different methods of preparation of hydrogen peroxide.

Explanation

Hydrogen peroxide can be prepared by following methods:
i) By acidifying barium peroxide : In this method, barium peroxide is acidified with sulphuric acid. The excess water is removed off by evaporation under reduced pressure.
`BaO_2 . 8H_2O (s) + H_2SO_4 (aq) to BaSO_4 (s) + H_2O_2 (aq) + 8H_2O (l)`
ii) By electrolytic oxidation of acidified sulphate solutions: Peroxodisulphate is obtained by electrolytic oxidation of acidified sulphate solutions. On hydrolysis, it gives hydrogen peroxide.
`2HSO_4^(- ) (aq) overset("electrolysis")(to) underset("peroxodisulphur")(HO_3 SOOSO_3(aq)) overset("Hydrolysis")(to) 2HSO_4^- (aq) + 2H^+ (aq) + H_2O_2 (aq)`