What is a buffer solution?

A buffer solution is characterized by its ability to resist changes in pH when small amounts of acids or bases are added. This property arises from the presence of a weak acid and its conjugate base (or a weak base and its conjugate acid) in the solution, which can react with added acids or bases to neutralize their effects. This balancing act maintains the pH within a relatively narrow range, making buffers essential in many biological and chemical processes where pH stability is crucial.

For instance, in biological systems, enzymes often function optimally at specific pH levels, and buffers help maintain these conditions despite varying metabolic activities. The ability to respond to pH changes without undergoing significant shifts is what defines a buffer solution, thereby making it a fundamental concept in chemistry and biochemistry.