On the basis of the following thermochemical data : $(\Delta f G^{\circ} H^+_{(aq)} = 0 ) $ <br> $ H_2O (\ell) \to H^+ (aq) + OH^- (aq); \Delta H= 57.32 \; kJ$ <br> $H_2 (g) + \frac{1}{2} O_2 (g) \to H_2O (\ell); \Delta H = -286.20 \; kJ$ <br> The value of enthalpy of formation of $OH^-$ ion at $25^{\circ}C$ is :
