Chemical and Ionic Equilibrium 2 Question 62
62. Calculate the $\mathrm{pH}$ of an aqueous solution of $1.0 \mathrm{M}$ ammonium formate assuming complete dissociation.
$\left(\mathrm{p} K_{a}\right.$ of formic acid $=3.8$ and $\mathrm{p} K_{\mathrm{b}}$ of ammonia $\left.=4.8\right)$
(1995, 2M)
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Solution:
- For salts of weak acid and weak base .
$$ \mathrm{pH}=7+\frac{1}{2}\left(\mathrm{p} K_{a}-\mathrm{p} K_{b}\right)=7+\frac{1}{2}(3.8-4.8)=6.50 $$
