Question

$1$ mole of ${CH}_{3}COOH$ and $1$ mole of ${CH}_{3}COONa$ are dissolved in water to form $1$ litre aqueous solution. The pH of the resulting solution will be:

• A. $9.2553$
• B. $4.7447$
• C. $14$
• D. $7$

Answer 1

Answer: (B)

$4.7447$

The mixture of ${CH}_{3}COOH$ and ${CH}_{3}COONa$ acts as a buffer.

$\therefore$ $pH={pK}_a+log\frac{\left[{CH}_{3}COONa\right]}{\left[{CH}_{3}COOH\right]}$

$={pK}_a+log\left(\frac{1}{1}\right)=4.7447+0=4.7447$