NCEA Level 3 Chemistry – Aqueous Chemistry (AS91393) Practice Exam

The buffer zone in a titration curve refers to the region where the pH remains relatively constant despite the addition of small amounts of titrant. This is a key characteristic of buffer solutions, which are designed to resist changes in pH when acids or bases are added. In this zone, the concentrations of the weak acid and its conjugate base (or vice versa) are both significant, allowing the solution to effectively neutralize added acids or bases. As a result, the pH does not change dramatically, making this region crucial for understanding the behavior of buffers in chemical reactions.

The other areas of the titration curve, such as those where pH changes significantly or where the titration point occurs, do not represent the buffer zone. While the point of maximum pH increase and the starting point of the titration are vital parts in the understanding of the titration process, they do not exhibit the stable pH characteristic of the buffer zone.