Q25 / 180 · KCET 2023 · Chemistry

A weak acid with $\mathrm{p} K_a 5.9$ and weak base with $\mathrm{p} K_b 5.8$ are mixed in equal proportions. $\mathrm{pH}$ of the resulting solution is

  • A
    $7.005$
  • B
    $7.5$
  • C
    $7$
  • Correct answer
    D
    $7.05$

Solution

$\mathrm{pH}$ of the resultant solution is given by, $\begin{aligned} \mathrm{pH} & =7+\frac{1}{2}\left(\mathrm{pK}_a-\mathrm{p} K_b\right)=7+\frac{1}{2}(5.9-5.8) \\ \mathrm{pH} & =7.05\end{aligned}$

Hence, the correct answer is option: 'D'.

Relevant Questions