Buffer solutions work by neutralizing added acids or bases through chemical reactions that involve the buffer components. When an acid is added, the conjugate base of the buffer reacts with the hydrogen ions. When a base is added, the weak acid in the buffer reacts with the hydroxide ions, thus maintaining a relatively constant pH.

Common components of a buffer include weak acids such as acetic acid, phosphoric acid, and their salts, like sodium acetate and disodium phosphate. These pairs are chosen based on the desired pH range and chemical stability.

To prepare a buffer solution, you typically mix a solution of a weak acid with a salt containing its conjugate base. The proportions depend on the desired pH, which can be predicted and adjusted using the Henderson-Hasselbalch equation.