pH and Buffers Defined

pH is a measure of the concentration of H⁺ [H₃O⁺] ions in a solution. Only the concentration of H⁺ and OH^- molecules determine the pH. When the concentration of H⁺ and OH^- ions are equal, the solution is said to be neutral. If there are more H⁺ than OH^- molecules the solution is acidic, and if there are more OH^- than H⁺ molecules, the solution is basic.

Buffers

To be able to add a strong acid or base to a solution without causing a large change in the pH, we need to create a buffer solution. A buffer solution contains both a weak acid (HA) and its conjugate base (A^-).