Final answer:
Buffers work by binding added hydrogen ions, preventing large swings in pH and keeping the pH level relatively constant within a solution. They convert strong acids or bases to their weaker forms through reversible reactions, but they have a finite capacity to buffer changes.
Step-by-step explanation:
When hydrogen ions are added to a solution, a buffer binds the hydrogen ions to remove them from the solution. This prevents sudden changes in pH and maintains a relatively constant pH level. In the context of an HC2H3O2/NaC2H3O2 buffer, for instance, if we add a strong acid to the buffer solution, the reaction will shift the equilibrium left, leading to the production of additional amounts of weak conjugate acid. Essentially, a buffer converts strong acids or bases to weak ones through reversible reactions, maintaining the pH balance within a narrow range and buffering the solution against dramatic changes.
However, it is crucial to note that buffer solutions have a limit to their capacity for buffering pH changes. Their effectiveness relies on the presence of substantial amounts of both members of the conjugate acid-base pair, and once these amounts are significantly depleted, the buffer's capacity is compromised.