Types of buffer solutions

There are two types of buffer solutions. Acidic buffer is used to maintain an acidic pH, while basic buffer maintains alkaline pH.

a. Acidic buffer solution : A solution containing a weak acid and its salt with strong base is called an acidic buffer solution.

For example : A solution containing weak acid such as $\mathrm{CH_3COOH}$ and its salt such as $\mathrm{CH_3COONa}$ is an acidic buffer solution.

pH of acidic buffer is given by the equation

and $K_a$ is the dissociation constant of the acid.

b. Basic buffer solution : A solution containing a weak base and its salt with strong acid is the basic buffer solution.

For example : A solution containing a weak base such as $\mathrm{NH_4OH}$ and its salt such as $\mathrm{NH_4Cl}$ is a basic buffer solution.

The pOH of basic buffer is given by,

$pOH = pK_b + \log_{10}\frac{[\text{salt}]}{[\text{base}]} \qquad \text{...(3.25)}$ …