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Question: Answered & Verified by Expert
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
ChemistryIonic EquilibriumJEE MainJEE Main 2008
Options:
  • A
    $9.58$
  • B
    $4.79$
  • C
    $7.01$
  • D
    $9.22$
Solution:
2332 Upvotes Verified Answer
The correct answer is:
$7.01$
It is a salt of weak acid and weak base
$$
\begin{aligned}
& {\left[\mathrm{H}^{+}\right]=\sqrt{\frac{\mathrm{K}_{\mathrm{w}} \times \mathrm{K}_{\mathrm{a}}}{\mathrm{K}_{\mathrm{b}}}}} \\
& \mathrm{pH}=7.01
\end{aligned}
$$

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