Q15 / 160 · AP EAMCET 2006 · Chemistry

Electrolysis of $X$ gives $Y$ at anode. Vacuum distillation of $Y$ gives $\mathrm{H}_2 \mathrm{O}_2$. The number of peroxy (O-O) bonds present in $X$ and $Y$ respectively are :

  • A
    1,1
  • B
    1,2
  • Correct answer
    C
    zero, 1
  • D
    zero, zero

Solution

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 $\left(\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8\right)$ which reacts with water during distillation to form $\mathrm{H}_2 \mathrm{O}_2$. $2 \mathrm{H}_2 \mathrm{SO}_4 \longrightarrow 2 \mathrm{H}^{+}+2 \mathrm{HSO}_4^{-}$ $2 \mathrm{HSO}_4^{-} \longrightarrow \mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8+2 e^{-}$(At anode) $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8+2 \mathrm{H}_2 \mathrm{O} \longrightarrow 2 \mathrm{H}_2 \mathrm{SO}_4+\mathrm{H}_2 \mathrm{O}_2$ ' $X$ ' is $\mathrm{H}_2 \mathrm{SO}_4$ and ' $Y$ ' is $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8$. So ' $X$ ' and ' $Y$ ' contains zero and one peroxy bond respectively.

Hence, the correct answer is option: 'C'.

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