Q21 / 160 · AP EAMCET 2016 · Chemistry

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

  • A
    $\mathrm{O}_2, \mathrm{H}_2$
  • Correct answer
    B
    $\mathrm{H}_2, \mathrm{O}_2$
  • C
    $\mathrm{H}_2, \mathrm{SO}_2
  • D
    $\mathrm{K}, \mathrm{SO}_2$

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.

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

Relevant Questions