Question

The pH of an aqueous solution at ${25}^{\circ }C$ having 0.1 M NaOH and 0.3 M to acetic acid ($p{K}_a$ = 4.76) would be nearly

• A. 4.25
• B. 4.45
• C. 4.75
• D. 5.05

Answer 1

The correct option is B

4.45

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

0.1 M NaOH will react with acid to form 0.1 M $C{H}_{3}COONa$ and therefore 0.3 $C{H}_3­COOH$ will be reduced to 0.2 M.

pH = 4.76 – log$\frac{0.2}{0.1}$ = 4.45