Question

$10\text{mL}$ of $2\text{M}$ acid is added to $250\text{mL}$ of a buffer solution with $pH=6.34$ and the $pH$ of the solution becomes $6.32$. The buffer capacity of the solution is:

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

The correct option is D $4$

$\text{Buffer capacity}=\frac{\text{moles of acid or base added per litre}}{\text{change in pH}}\text{Buffer capacity}=\frac{\frac{2\times 10}{1000}\times \frac{1000}{250}}{6.34-6.32}=4$