Chemistry - Ionic Equilibrium Question with Solution | TestHub

The pair ${\mathrm{HNO}}_2$ and ${\mathrm{NaNO}}_2$ constitutes a buffer because ${\mathrm{HNO}}_2$ is a weak acid and ${\mathrm{NaNO}}_2$ is a salt of a weak acid $\left({\mathrm{HNO}}_2\right)$ with a strong base $(\mathrm{NaOH})$. Hence, it is an example of an acidic buffer solution. Caution Solutions of a weak acid and its conjugate base or weak base and its conjugate acid are able to maintain $\mathrm{pH}$ forming buffer solutions.