(7) What is the pH after adding 10.0 mL of potassium hydroxide?
In this situation, the weak acid acts like a buffer, so the Henderson-Hasselbach equation applies. The acid dissociates according to the equilibrium
The Henderson-Hasselbach equation then yields
Although concentrations are given in mmol/mL, both the conjugate base and the acid occupy the same volume. Therefore, the volumes in the denominators cancel, and equation (16) can be rewritten as
