Chemistry - Ionic Equilibrium Question with Solution | TestHub

Find pH of solution containing 0.5 mole ${\mathrm{H}}_3{\mathrm{PO}}_4$ and 0.5 mole ${\mathrm{Na}}_2{\mathrm{HPO}}_4$. [Take for ${\mathrm{H}}_3{\mathrm{PO}}_4{\mathrm{K}}_{{\mathrm{a}}_1}=10^{-3},{\mathrm{K}}_{{\mathrm{a}}_2}=10^{-7},{\mathrm{K}}_{{\mathrm{a}}_3}=10^{-13}$ ]