Chemical and Ionic Equilibrium 2 Question 37
37. Aqueous solutions of $\mathrm{HNO}{3} \mathrm{KOH}, \mathrm{CH}{3} \mathrm{COOH}$ and $\mathrm{CH}_{3} \mathrm{COONa}$ of identical concentrations are provided. The pair(s) of solutions which form a buffer upon mixing is(are)
(a) $\mathrm{HNO}{3}$ and $\mathrm{CH}{3} \mathrm{COOH}$
(2010)
(b) $\mathrm{KOH}$ and $\mathrm{CH}_{3} \mathrm{COONa}$
(c) $\mathrm{HNO}{3}$ and $\mathrm{CH}{3} \mathrm{COONa}$
(d) $\mathrm{CH}{3} \mathrm{COOH}$ and $\mathrm{CH}{3} \mathrm{COONa}$
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Solution:
- In $\mathrm{HNO}{3}$ and $\mathrm{CH}{3} \mathrm{COONa}$ combination, if $\mathrm{HNO}{3}$ is present in limiting amount, it will be neutralised completely, leaving behind some excess of $\mathrm{CH}{3} \mathrm{COONa}$.
$$ \underset{\text { Buffer combination }}{\mathrm{CH}{3} \mathrm{COONa}+\mathrm{HNO}{3} \longrightarrow \mathrm{CH}{3} \mathrm{COOH}}+\mathrm{NaNO}{3} $$
