The products obtained at the cathode and anode respectively during the electrolysis of aqueous $\mathrm{K}_2…

The products obtained at the cathode and anode respectively during the electrolysis of aqueous $\mathrm{K}_2 \mathrm{SO}_4$ solution using platinum electrodes are
  1. $\mathrm{O}_2, \mathrm{H}_2$
  2. $\mathrm{H}_2, \mathrm{O}_2$
  3. $\mathrm{H}_2, \mathrm{SO}_2
  4. $\mathrm{K}, \mathrm{SO}_2$

Solution

$\mathrm{K}_2 \mathrm{SO}_4 \rightarrow 2 \mathrm{~K}^{-1}+\mathrm{SO}_4^{2-}$ Due to platinum electrodes, self ionization of water will take place. $\mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{H}^{+}+\mathrm{OH}^{-}$ At cathode: $2 \mathrm{H}^{+}+2 \mathrm{e}-\rightarrow \mathrm{H}_2$ At anode: $\mathrm{OH} \rightarrow 2 \mathrm{H}_2 \mathrm{O}+\mathrm{O}_2+4 \mathrm{e}$ Due to lower electrode potentials, $\mathrm{H}_2$ gas will generate at cathode and $\mathrm{O}_2$ gas will generate at anode.

Asked in: AP EAMCET 2016

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