What is the main role of buffers in a solution?

Buffers play a critical role in maintaining a stable pH in a solution despite the addition of acids or bases. They accomplish this by using a weak acid and its conjugate base (or a weak base and its conjugate acid) to neutralize small amounts of added protons (H⁺) or hydroxide ions (OH⁻). This resistance to changes in pH is essential in many biological and chemical processes where a specific pH range is necessary for optimal functioning.

For instance, in biological systems, enzymes typically operate within a narrow pH range; thus, the presence of buffers helps ensure that enzymatic reactions proceed efficiently by maintaining the appropriate pH. Without buffers, even minor alterations in the concentration of hydrogen ions could lead to significant shifts in pH, potentially disrupting biological activity and processes.

In summary, the main function of buffers in a solution is to resist changes in pH, making them vital for various chemical and biological applications.