A buffer solution is related to Le Chatelier's principle because it resists changes to the pH of a solution when small amounts of acid or base are added. According to Le Chatelier's principle, when a stress is applied to a system at equilibrium, the system will shift in such a way as to counteract the stress and restore equilibrium. In the case of a buffer solution, if an acid or base is added, the buffer system will absorb or release some of the H+ or OH- ions to resist the change in pH and maintain the equilibrium. This is possible due to the buffer solution's ability to contain a weak acid and its conjugate base or a weak base and its conjugate acid.
