A pH buffer solution is a special type of solution that resists changes in pH when small amounts of acids or bases are added. It typically consists of a weak acid and its conjugate base, or a weak base and its conjugate acid. This balance helps maintain a stable pH level, which is crucial in many chemical and biological processes. Buffers are essential in various applications, including biological systems, where enzymes function optimally at specific pH levels. They are also used in laboratory experiments, agriculture, and aquarium management to ensure that the environment remains suitable for living organisms and chemical reactions.