Explanation

(c)
A 30% solution of hydrogen peroxide can be obtained by the electrolysis of 50% sulphuric acid followed by vacuum distillation. The first product of electrolysis is perdisulphuric acid $\left( H_{2}S_{2}O_{8} \right)$ which reacts with water during distillation to form $H_{2}O_{2}.$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 2H_{2}SO_{4}\ \rightarrow 2H^{+} + \ 2HSO_{4}^{-}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 2HSO_{4}^{-}\ \rightarrow H_{2}S_{2}O_{8} + \ 2e^{-}$ (At anode)
$\ H_{2}S_{2}O_{8} + \ 2H_{2}O\ \rightarrow 2H_{2}SO_{4} + \ H_{2}O_{2}$
$‘X’\ is\ H_{2}SO_{4}\ and\ \ \ 'Y^{'}{isH}_{2}S_{2}O_{8}.\$ So, ‘X’ and ‘Y’ contains zero and one peroxy bond respectively.