Chemistry - Electrochemistry Question with Solution | TestHub

During the electrolysis of molten NaCl:
At cathode: ${\mathrm{Na}}^{+}+{\mathrm{e}}^{-}\to {\mathrm{Na}}_{(\mathrm{s})}$
At anode: $2{\mathrm{Cl}}^{-}\to {\mathrm{Cl}}_{2(\mathrm{g})}+2{\mathrm{e}}^{-}$

During the electrolysis of aqueous NaCl:
At cathode: $2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}+2{\mathrm{e}}^{-}\to {\mathrm{H}}_{2(\mathrm{g})}+2{\mathrm{OH}}_{(\mathrm{aq})}^{-}$ (since the reduction potential of water is higher than that of ${\mathrm{Na}}^{+}$)
At anode: $2{\mathrm{Cl}}^{-}\to {\mathrm{Cl}}_{2(\mathrm{g})}+2{\mathrm{e}}^{-}$ (due to overvoltage of ${\mathrm{O}}_2$, ${\mathrm{Cl}}_2$ is liberated instead of ${\mathrm{O}}_2$)

Thus, the liberation of ${\mathrm{Cl}}_2$ gas at the anode is common to both processes.

Answer: ${\mathrm{Cl}}_2$ gas is liberated at anode.