Chemistry - Ionic Equilibrium Question with Solution | TestHub

For buffer solution $\begin{array}{rl}& \mathrm{pH}={\mathrm{pK}}_{\mathrm{a}}+\log \frac{[\text{ Salt }]}{[\text{ Acid }]}\\ & =4.5+\log \frac{[\text{ Salt }]}{[\text{ Acid }]}\end{array}$ as $\mathrm{HA}$ is $50\%$ ionized so $[\text{Salt}]$=$[\text{Acid}]$ $\begin{array}{rl}& \mathrm{pH}=4.5\\ & \mathrm{pH}+\mathrm{pOH}=14\\ & \Rightarrow \mathrm{pOH}=14-4.5=9.5\end{array}$ Hence (C) is correct.