At what point in the following titration curve for a weak acid being titrated with a strong base is the pH equal to the pK_a of the acid? The x-axis scale goes from 0.0 mL to 20.0 mL. The sharp rise is at 10.0 mL.

Question

Quizplus · Accepted Answer

At the half-equivalence point, the [A-] = [HA], so pH = pKa. The half-equivalence point is where exactly half of the acid has been neutralized by the base. In this case, the equivalence point is at 10.0 mL, so the half-equivalence point would be at 5.0 mL (halfway to the equivalence point). Therefore, the pH would be equal to pKa at 5.0 mL.

At What Point in the Following Titration Curve for a Weak