3 g of acetic acid is added to 250 mL of 0.1 M HCl and the solution made up to 500 mL. To 20 mL of this solution 1/2 mL of 5 M NaOH is added. The pH…

$\displaystyle 3$ g of acetic acid is added to $\displaystyle 250$ mL of $\displaystyle 0.1$ M HCl and the solution made up to $\displaystyle 500$ mL. To $\displaystyle 20$ mL of this solution $\displaystyle \frac{1}{2} \mathrm{~mL}$ of $\displaystyle 5$ M NaOH is added. The pH of the solution is \_\_\_\_. [Given : pKa of acetic acid $\displaystyle =4.75$, molar mass of acetic acid=$\displaystyle 60$ g/mol, $\displaystyle \log 3=0.4771$ ]Neglect any changes in volume.