What is the function of a buffer in a chemical solution?

A buffer plays a crucial role in maintaining a stable pH in a chemical solution. It does this by resisting changes in hydrogen ion concentration when acids or bases are added to the solution. This ability is essential in many chemical and biological processes, as many reactions and biological activities are highly sensitive to pH changes.

Buffers typically consist of a weak acid and its conjugate base or a weak base and its conjugate acid. When an acid is introduced, the weak base component reacts with the excess hydrogen ions, minimizing the change in pH. Conversely, if a base is added, the weak acid component can donate protons to neutralize the added base. This dynamic equilibrium keeps the solution's pH relatively constant, allowing for optimal conditions for various reactions and processes.

While other functions concerning solution chemistry are important, they do not accurately describe the primary role of a buffer. Thus, maintaining a stable pH is the defining characteristic of buffer systems in chemical solutions.