Question

A solution is $0.1MC{H}_{3}COOH$ and $0.1MC{H}_{3}COONa$. Which of the following will change the $pH$ significantly, of the solution?

• A. Addition of water
• B. Addition of $C{H}_{3}COONa$ without change in volume
• C. Addition of $C{H}_{3}COOH$ without change in volume
• D. None will change the $pH$ significantly

Answer 1

The correct option is D None will change the $pH$ significantly

A solution that resists change in $pH$ value upon addition of a small amount of strong acid or base (less than $1$%) or when the solution is diluted is called buffer solution.

The capacity of a solution to resist alteration in its $pH$ value is known as buffer capacity and the mechanism of buffer solution is called buffer action.

Acidic buffer solution: An acidic buffer solution consists of a solution of a weak acid and its salt with a strong base.

Here, it is an acidic buffer solution with same concentration of acid and salt.

$pH=p{K}_a+log\frac{\left[salt\right]}{\left[acid\right]}$

So as volume of solution remain constant $pH$ will remain constant.