At the equivalence point during the titration of a weak acid with a strong base, would the pH be acidic, neutral, or basic?

• A. Basic
• B. Acidic
• C. Neutral

Answer: (A)

Verified step by step guidance

1. Understand what happens at the equivalence point in a titration: it is the point where the amount of strong base added exactly neutralizes the weak acid present.
2. Recognize that the weak acid (HA) reacts with the strong base (OH⁻) to form its conjugate base (A⁻) and water, according to the reaction: \(\mathrm{HA + OH^- \rightarrow A^- + H_2O}\).
3. At the equivalence point, all the weak acid has been converted to its conjugate base (A⁻), which remains in solution.
4. Since the conjugate base (A⁻) is the conjugate of a weak acid, it can hydrolyze with water to produce OH⁻ ions, increasing the pH: \(\mathrm{A^- + H_2O \rightleftharpoons HA + OH^-}\).
5. Therefore, the solution at the equivalence point is basic because of the presence of the conjugate base that raises the pH above 7.