Editing Buffer solution (section)

===Simple buffering agents===
:{| class="wikitable"
! Buffering agent !! p''K''<sub>a</sub> !! Useful pH range
|-
| [[Citric acid]] || 3.13, 4.76, 6.40 || 2.1–7.4
|-
| [[Acetic acid]] || 4.8 || 3.8–5.8
|-
| [[potassium dihydrogenphosphate|KH<sub>2</sub>PO<sub>4</sub>]] || 7.2 || 6.2–8.2
|-
| [[N-Cyclohexyl-2-aminoethanesulfonic acid|CHES]] || 9.3 || 8.3–10.3
|-
| [[Borate]] || 9.24 || 8.25–10.25
|}
For buffers in acid regions, the pH may be adjusted to a desired value by adding a strong acid such as [[hydrochloric acid]] to the particular buffering agent. For alkaline buffers, a strong base such as [[sodium hydroxide]] may be added. Alternatively, a buffer mixture can be made from a mixture of an acid and its conjugate base. For example, an acetate buffer can be made from a mixture of acetic acid and [[sodium acetate]]. Similarly, an alkaline buffer can be made from a mixture of the base and its conjugate acid.