Final answer:
A good buffer is composed of significant amounts of a weak acid and its conjugate base, which enable it to resist changes in pH when strong acids or bases are added to the solution.
Step-by-step explanation:
Identifying a good buffer depends on the conjugate acid-base pair and the pH stability they provide to a solution. A good buffer typically consists of significant amounts of both a weak acid and its conjugate base. This combination is crucial for the buffer's ability to neutralize added strong acids or bases and maintain a stable pH.
Buffers work by using the weak acid to neutralize bases and the conjugate base to neutralize acids. For instance, in an acetic acid/sodium acetate buffer system, when a strong acid is added, the increase in hydronium ions shifts the equilibrium, leading to the consumption of acetate ions and generation of more acetic acid. Conversely, adding a strong base will cause the acetate ions to neutralize the added base, shifting the equilibrium and generating more acetate ions from acetic acid.
Higher buffer capacity is associated with higher amounts of weak acid and conjugate base. This capacity ensures that the buffer efficiently minimizes pH changes, despite the addition of strong acids or bases to the solution.