Question

What is a buffer solution? How is it prepared? Explain the buffer action of a basic buffer with a suitable example.

Answer 1

Solutions which reserve acidity or alkalinity or which resists change of pH on the addition of small amounts of acid or alkali are called Buffer solution.
Prepared by addition of acid or base depending on which they are respectively called acidic and basic Buffer.
Basic Buffer : When a drop of strong acid say $HCl$ is added,
$N{H}_{4}OH\rightleftharpoons N{H}_4^{+}+O{H}^{-}$
$\begin{array}{cccc}HCl& \rightleftharpoons & {Cl}^{-}+& H^{+}\\ & & \upharpoonleft \downharpoonright & \upharpoonleft \downharpoonright \\ & & N{H}_{4}Cl& H_{2}O\end{array}$
Feebly ionised
The $O{H}^{-}$ ions produced from $N{H}_{4}OH$ combines with $H^{+}$ ions produced from $HCl$ to form feebly ionized water molecule and therefore, the pH value does not change appreciably.