A 1500 mL solution contains 3022 grams of sodium benzoate an

A 150.0 mL solution contains 3.022 grams of sodium benzoate and 3.520 grams of benzoic acid. Calculate the pH of this soultion.

Solution

For buffer, pH = pKa + log[salt/acid]

Here, [salt] = (3.022/144.11)/0.150 M

[acid] = (3.520/122.12)/0.150 M

Hence, pH = 4.2 + log[0.7275]

pH = 4.06