A buffer solution is a mixture of a weak Brønsted acid and its conjugate base that resists changes in pH when small amounts of strong acid or base are added. Added acid is neutralised by the conjugate base, and added base by the weak acid, so the pH changes only slightly. Buffers are essential for keeping the pH of biological and chemical systems nearly constant.

缓冲溶液是由弱布朗斯特酸及其共轭碱组成的混合物,在加入少量强酸或强碱时能抵抗 pH 的变化。所加入的酸被共轭碱中和,所加入的碱被弱酸中和,因而 pH 只略有改变。缓冲溶液对于使生物和化学体系的 pH 几乎保持恒定至关重要。