Chapter 15, Problem 64P

Phthalic acid ( ${\text{H}}_{\text{2}}{\text{C}}_{\text{8}}{\text{H}}_{\text{4}}{\text{O}}_{\text{4}},$ abbreviated ${\text{H}}_{\text{2}}\text{Ph}$ ) is a diproticacid. Its ionization in water at 25°C takes place in twosteps:
   $\begin{array}{l}{\text{H}}_{\text{2}}\text{Ph}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(\mathcal{l}\right)\underset{}{\overset{}{\rightleftarrows }}{\text{H}}_{\text{3}}{\text{O}}^{+}\left(aq\right)+{\text{HPh}}^{-}\left(aq\right)K_{a1}=1.26\times {10}^{-3}\\ {\text{H}}_{\text{2}}{\text{Ph}}^{\text{-}}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(\mathcal{l}\right)\underset{}{\overset{}{\rightleftarrows }}{\text{H}}_{\text{3}}{\text{O}}^{+}\left(aq\right)+{\text{Ph}}^{2-}\left(aq\right)K_{a2}=3.10\times {10}^{-6}\end{array}$
If 0.0100 mol of phthalic acid is dissolved per liter ofwater, calculate the equilibriumconcentrations of ${\text{H}}_{\text{2}}\text{Ph},HP{h}^{-},{\text{Ph}}^{2-},$ and ${\text{H}}_{\text{3}}{\text{O}}^{+}.$