Chemistry - Ionic Equilibrium Question with Solution | TestHub

Glycine ${\mathrm{H}}_3{\mathrm{N}}^{+}{\mathrm{CH}}_2{\mathrm{COO}}^{-}$is more acidic than basic. Instead of $K_b$ value, the second given $K_a$ value is corresponding to the $K_b$ value $\left(\because K_a\times K_b=10^{-14}\right)$. Hence, overall ionization constant, $$\begin{array}{rl}& K=K_{a_1}\times K_{a_2}=4.5\times 10^{-3}\times 1.7\times 10^{-10}\\ & =7.65\times 10^{-13}\\ & {\mathrm{H}}^{+}=\sqrt{KC}=\sqrt{7.65\times 10^{-13}\times 0.01}\\ & =\sqrt{0.765\times 10^{-14}}=0.87\times 10^{-7}\mathrm{M}\\ & \mathrm{pH}=-\log \left(0.87\times 10^{-7}\right)=7.06\\ & \end{array}$$