lahus, millel on võime (teatud määral) säilitada oma pH väärtust nii lahjendamisel kui ka väikese koguse tugeva happe või leelise lisamisel
nõrk happe või aluse lahus koos vastava soola lisandiga, et lahuse vesinikioonide sisaldus (pH) püsiks reaktsiooni ajal võimalikult muutumatuna
a solution that resists change in pH when small amounts of an acid or alkali are added over a certain range or when the solution is diluted
a solution to which moderate amounts of either a strong acid or base may be added without causing any large change in the pH value of the solution. Such solutions usually contain (a) a weak acid and a salt of the weak acid, (b) a mixture of an acid salt with the normal salt, or (c) a mixture of two acid salts.
In the laboratory, buffers are used to prepare solutions of known stable pH. Natural buffers occur in living organisms, where the biochemical reactions are very sensitive to change in pH. The main natural buffers are H2CO3/HCO3 − and H2PO4 −/HPO42−. Buffer solutions are also used in medicine (e.g. in intravenous injections), in agriculture, and in many industrial processes (e.g. dyeing, fermentation processes, and the food industry).
