Brine is electrolysed by using inert electrodes. The reaction at anode is_______

Options

A. `Cl_((aq))^(-) to 1/2 Cl_(2(g)) + e^(-), E_("cell")^(@)=1.36V`
B. `2H_(2)O_((l)) to O_(2(g)) + 4H^(+) +4e^(-),E_("cell")^(@)=1.23V`
C. `Na_((aq))^(+) + e^(-) to Na_((s)),E_("cell")^(@)=2.71V`
D. `H_((aq))^(+) to 1/2 H_(2(g)),E_("cell")^(@)=0.00 V`

Answer

A

Explanation

Although reduction potential of `Cl^(-)` ion is higher than that of `H_(2)O`, yet oxidation of `Cl^(-)` ions occurs in preference to `H_(2)O` due to overvoltage of `O_(2)` (i.e., water needs greater voltage for oxidation to `O_(2)` as it is a kinetically slow process).