The standard emf of the cell $\left({\mathrm{E}}_{\text{cell }}°\right.$ and equilibrium constant $\left({\mathrm{K}}_{\mathrm{eq}}\right)$ of the following reaction of $298 \mathrm{K}$

${\mathrm{Cd}}^{2+}+4{\mathrm{NH}}_3\rightleftharpoons \mathrm{Cd}{\left({\mathrm{NH}}_3\right)}_4^{2+}$

The standard e.m.f. of the cell, $\mathrm{Cd}\left(\mathrm{s}\right)\left|{\mathrm{CdCl}}_2\left(\mathrm{aq}\right)\left(0.1\mathrm{M}\right)\right|\left|\mathrm{AgCl}\left(\mathrm{s}\right)\right|\mathrm{Ag}\left(\mathrm{s}\right)$ in which the cell reaction is $\mathrm{Cd}\left(\mathrm{s}\right)+2\mathrm{AgCl}\left(\mathrm{s}\right)⟶2\mathrm{Ag}\left(\mathrm{s}\right)+{\mathrm{Cd}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$ is $0.6915 \mathrm{V}$ at $0°\mathrm{C}$ and $0.6753 \mathrm{V}$ at $25°\mathrm{C}$. The enthalpy change of the reaction at $25°\mathrm{C}$ is