Chapter 14, Problem 14.29QP

The following equilibrium constants have been determined for hydrosulfuric acid at 25°C:

$\begin{array}{l}{\text{H}}_2\text{S(}aq\text{)}\stackrel{}{\rightleftharpoons }{\text{H}}^{+}(aq)+{\text{HS}}^{-}(aq)\\ K{\text{'}}_{\text{c}}=9.5\times {10}^{-8}\\ {\text{HS}}^{-}\text{(}aq\text{)}\stackrel{}{\rightleftharpoons }{\text{H}}^{+}(aq)+{\text{S}}^{2-}(aq)\\ K{"}_{\text{c}}=1.0\times {10}^{-19}\end{array}$

Calculate the equilibrium constant for the following reaction at the same temperature:

${\text{H}}_2\text{S(}aq\text{)}\stackrel{}{\rightleftharpoons }2{\text{H}}^{+}(aq)+{\text{S}}^{2-}(aq)$