Key Concepts and Summary
A solution containing a mixture of a weak acid and its conjugate base, or of a weak base and its conjugate acid, is called a buffer solution. The presence of a weak conjugate acid-base pair provides reactants that may neutralize small additions of strong acid or base, yielding weaker conjugate partners. The hydronium ion concentration of a buffer solution therefore does not change significantly when a small amount of acid or base is added.
- pKa = −log Ka
- pKb = −log Kb
amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one pH unit)
mixture of a weak acid or a weak base and the salt of its conjugate; the pH of a buffer resists change when small amounts of acid or base are added
equation used to calculate the pH of buffer solutions