The $\mathrm{pK}_{\mathrm{a}}$ of a weak acid, $\mathrm{HA}$, is $4.80$. The $\mathrm{pK}_{\mathrm{b}}$ of a…
The $\mathrm{pK}_{\mathrm{a}}$ of a weak acid, $\mathrm{HA}$, is $4.80$. The $\mathrm{pK}_{\mathrm{b}}$ of a weak base, $\mathrm{BOH}$, is $4.78$. The $\mathrm{pH}$ of an aqueous solution of the corresponding salt, BA, will be
$9.58$
$4.79$
$7.01$
$9.22$
Solution
It is a salt of weak acid and weak base
$
\begin{aligned}
& {\left[\mathrm{H}^{+}\right]=\sqrt{\frac{\mathrm{K}_{\mathrm{w}} \times \mathrm{K}_{\mathrm{a}}}{\mathrm{K}_{\mathrm{b}}}}} \\
& \mathrm{pH}=7.01
\end{aligned}
$