$25\% ;\,\,\,pH = {p^{{K_a}}} + \log \frac{{Salt}}{{Acid}}\,\,\,pH = {p^{{K_a}}} + \log \frac{{25}}{{75}}$
$50\% \,pH = {p^{{K_a}}} + \log \frac{{50}}{{50}}\,\,\,\,75\% \,pH = {p^{{K_a}}} + \log \frac{{75}}{{25}}$
[આપેલ છે : $pKa$ (એસિટિક ઍસિડ) $=4.74$ ]