Which of the following solution produces $\mathrm{H}_2 \mathrm{O}_2$ on electrolysis?

Which of the following solution produces $\mathrm{H}_2 \mathrm{O}_2$ on electrolysis?
  1. $0.2 \mathrm{~N} \mathrm{NaOH}$
  2. $50 \% \mathrm{H}_2 \mathrm{SO}_4$
  3. $2 \% \mathrm{H}_2 \mathrm{SO}_4$
  4. $5 \% \mathrm{NaCl}$

Solution

$\mathrm{H}_2 \mathrm{O}_2$ is obtained by the electrolysis of a cold $50 \%$ solution of $\mathrm{H}_2 \mathrm{SO}_4$ $ \mathrm{H}_2 \mathrm{SO}_4 \rightleftharpoons \mathrm{H}^{+}+\mathrm{HSO}_4^{-} $ The electrolysis of $\mathrm{HSO}_4^{-}$ion gives $\mathrm{H}_2 \mathrm{O}_2$. Peroxodisulphate obtained by electrolytic oxidation of acidified sulphate solutions at high current density, on hydrolysis yield hydrogen peroxide. $ \begin{aligned} & 2 \mathrm{HSO}_4^{-} \xrightarrow[-2 e^{-}]{\text {Electrolysis }} \underset{\substack{\text { Peroxodisulphate } \\ \mathrm{HO}_3 \mathrm{SOOSO}_3 \mathrm{H}(a q)}}{\text { Hydrolysis }} \underset{2 \mathrm{H}_2 \mathrm{O}}{\longrightarrow} \\ & 2 \mathrm{SO}_4^{2-}(a q)+4 \mathrm{H}^{+}(a q)+\mathrm{H}_2 \mathrm{O}_2(a q) \end{aligned} $

Asked in: AP EAMCET 2021 (25 Aug Shift 2)

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