In the chemical sense of the word, buffers are those systems that tend to maintain a constant pH level despite the addition (within certain limits) of an acid or base or despite dilution. They usually consist of mixtures of either a weak acid and a salt formed from the acid and a strong base, or they consist of a weak base and a salt formed from the base and a strong acid. Many chemical reactions and all biological processes take place only at specific pH levels. If there is no buffer action, hydrogen‐ion concentration may alter and cause the reaction to slow down until it stops, or produce products different from those required.
Theory
Using the case of an aqueous solution of acetic acid and sodium acetate – i.e., a mixture of a weak acid and its salt formed from a strong base – the dissociation equilibrium of the acid and the relative constant can be represented by
The hydrolysis equilibrium of the salt and the relative constant can be represented by
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Bache, B., Chesworth, W., Chesworth, W., Gessa, C. (2008). Buffers, Buffering. In: Chesworth, W. (eds) Encyclopedia of Soil Science. Encyclopedia of Earth Sciences Series. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-3995-9_79
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