Question

The pH of a buffer is $4.745$. When $0.01mole$ of $NaOH$ is added to $1$ litre of it, the pH changes to $4.832$, calculate its buffer capacity.

Answer 1

From definition
Buffer capacity $\left(\varphi \right)=\frac{\partial b}{\partial \left[pH\right]}$
$\partial \left[pH\right]=(4.832-4.745)=0.087;\partial b=0.01$
Substituting given values
$\varphi =\frac{0.01}{0.087}=0.115$