In the electrolysis of aqueous sodium chloride solution which of the hall cell reaction will occur at anode?

Options

A. `Na_((aq))^(+) + e^(-) to Na_((s)) , E_"cell"^@`=-2.71 V
B. `2H_2O_((l)) to O_(2(g)) + 4H_((aq))^(+) + 4e^(-) , E_"cell"^@`=1.23 V
C. `H_((aq))^(+) + e^(-) to 1/2H_(2(g)) , E_"cell"^@` =0.00 V
D. `Cl_((aq))^(-) to 1/2Cl_(2(g)) + e^(-) ,E_"cell"^@` =1.36 V

Answer

D

Explanation

At the anode, the following oxidation reactions are possible :
(d)`Cl_((aq))^(-) to 1//2Cl_(2(g)) + e^(-) , E_"cell"^@`=1.36 V
(b)`2H_2O_((l)) to O_(2(g)) + 4H_((aq))^+ + 4e^(-) , E_"cell"^@`=1.23 V
The reaction at anode with lower value of `E^@` is preferred and therefore , water should get oxidised in preference to `Cl_((aq))^-` However, on account of overpotential of oxygen , reaction (d) is preferred.