Question

Electrolysis of aqueous sodium chloride solution will form _____at the cathode.

• A. Hydrogen gas
• B. sodium metal
• C. water
• D. chlorine gas

Answer 1

The correct option is A Hydrogen gas

Electrolysis of aq NaCl will form hydrogen gas at the cathode.
Other products will be NaOH (aq) and $C{l}_2$ gas.

$NaCl\rightleftharpoons N{a}^{+}+C{l}^{-}$
$H_{2}O\rightleftharpoons H^{+}+O{H}^{-}$

On passing electricity, $N{a}^{+}$and $H^{+}$ ions move towards cathode. Cl¯ and OH¯ ions move towards anode.

The discharge potential of $H^{+}$ ions is less negative than Na+ ions. Thus $H^{+}$ ions get discharged easily and hydrogen is liberated at cathode.

Cl¯ ions get discharged easily and $C{l}_2$ is liberated at anode as the discharge potential of Cl¯ ions is less than OH¯ ions.