Which statement about buffer solutions is true?

Buffer solutions are designed to maintain a relatively stable pH when small amounts of acids or bases are added to them. This is possible because buffers typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid. When an acid is added to a buffer, the weak base component will react with the excess hydrogen ions (from the acid) to minimize pH changes. Similarly, when a base is introduced, the weak acid component can donate protons to neutralize the added hydroxide ions.

This dual-action capability allows buffers to effectively resist changes in pH, ensuring they can maintain a specific pH range even in the presence of both acidic and basic substances. As a result, when considering the functionality of buffer solutions, the statement that they can maintain pH upon the addition of either acids or bases accurately reflects their purpose and operation in chemical systems.