A buffer solution is a special type of solution that resists changes in pH when small amounts of an acid or base are added. It typically consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. This balance allows the solution to maintain a relatively stable pH, which is crucial in many chemical and biological processes. Buffer solutions are commonly used in laboratories and various industries, including biochemistry and pharmaceuticals. They help ensure that reactions occur under optimal conditions, as many enzymes and biochemical reactions are sensitive to pH changes.