What is standard enthalpy of reaction for the following reaction $\frac{1}{2}{\mathrm{H}}_2\left(\mathrm{g}\right)+\mathrm{AgCl}\left(\mathrm{s}\right)\to \mathrm{Ag}\left(\mathrm{s}\right)+{\mathrm{H}}^{+}+{\mathrm{Cl}}^{-}$ given  ${\mathrm{\Delta H}}_{\mathrm{f}\left(\mathrm{AgCl}\right)}^0=-30360{\mathrm{calmol}}^{-1}$

${\mathrm{\Delta H}}_{\mathrm{f}}^0\left({\mathrm{Cl}}^{-}\right)=-40020\mathrm{cal}$