Final answer:
Buffer capacity refers to the amount of strong acid or base a buffer can absorb before the pH changes significantly, dependent on the concentrations of the buffer components.
Step-by-step explanation:
Buffer capacity is defined as the amount of strong acid or base that can be absorbed by a buffer solution before there is a significant change in pH. It is related to the concentrations of the weak acid and its conjugate base within the buffer. The higher the concentration of these components, the greater the buffer's capacity to resist changes in pH when strong acids or bases are added to the solution. This capacity is crucial in maintaining a stable environment in biological systems and industrial applications where pH needs to be controlled.
PKa, the acid dissociation constant, influences the pH range over which a buffer is effective. A solution will maintain its highest buffer capacity when the pH is within one unit above or below the pKa of the buffering agent. Therefore, understanding the relationship between buffer capacity, pH, and pKa is essential when designing buffer solutions for various purposes.
The effectiveness of a buffer is also related to its pKa, where the optimum buffering capacity is within one pH unit of the pKa.