Which type of solution resists changes in pH?

A buffer solution is a special type of solution that is designed to resist changes in pH when small amounts of an acid or base are added. Buffers typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid. This combination allows them to maintain a relatively stable pH level by neutralizing added acids or bases.

For instance, if an acid is added to a buffer solution, the weak base component will react with the added hydrogen ions to minimize the change in pH. Conversely, if a base is added, the weak acid component will donate hydrogen ions to counteract the increase in pH. This property makes buffer solutions essential in many biological and chemical processes where maintaining a specific pH is crucial for proper functioning.

Other types of solutions, such as acidic or pH neutral solutions, do not have this ability to stabilize pH changes effectively. Salt solutions vary, but they typically do not provide the specific buffering action needed to resist pH changes unless they are formulated with specific buffering components.