Give any two methods of preparation of `H_2O_2`.

Explanation

`H_2O_2` can be prepared by adding a metal peroxide to dilute acid.
(i) `BaO_2(s)+H_2SO_4(aq)toBaSO_4(s)+H_2O_2(aq)`
(ii) `Na_2O_2(s)+H_2SO_4(aq)to2Na+(aq)+SO_4^(2-)(aq)+H_2O_2(aq)`