Assertion (A) : Electrolysis of NaCl solution gives chlorine at anode instead of oxygen

Reason (R) : Formation of oxygen at anode requires over potential

In the electrolysis of NaCl solution, chlorine is produced at anode instead of 0₂. The two half-cell reactions are:
$$\begin{gathered} 2{\mathrm{Cl}}^{-}\to {\mathrm{Cl}}_2 +2\stackrel{-}{\mathrm{e}} ,{\mathrm{E}}^0=1.36\mathrm{v} \\ 2{\mathrm{H}}_2\mathrm{O} \to {\mathrm{O}}_2\left(\mathrm{g}\right) +4{\mathrm{H}}^{+} +4\stackrel{-}{\mathrm{e}} ,{\mathrm{E}}^0=1.23\mathrm{v} \end{gathered}$$
Lower value of E Cell is preferred but due to overvoltage chlorine is liberated at anode.so Both ‘A’ and ‘R’ are true and ‘R’ is the correct explanation of ‘A’