What is a buffer solution?

A buffer solution is defined as a solution that resists changes in pH when small amounts of an acid or a base are added. This characteristic is crucial in many biological and chemical processes, as maintaining a stable pH is essential for the proper functioning of enzymes and biochemical reactions. Buffers typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid, enabling them to neutralize added acids or bases effectively and maintain a relatively constant pH level.

In contrast, a solution that changes pH rapidly fails to maintain this stability, and a solution that is always neutral does not fulfill the function of a buffer because it does not respond to the addition of acids or bases. Lastly, while some buffer solutions might support bacterial growth, behaving this way is not a defining feature of all buffers. The primary role of a buffer is its ability to maintain pH levels rather than promoting any biological processes.