Partitioning of acids and bases

Berthollet reasoned that such an exchange of bases did not take place because the partition of acids and bases was in effect. When the exchange did occur, it was due not to the affinities in action, but to other real causes such as crystallization and precipitation. Chemists had inadvertently ascribed the strongest affinities to the substances that precipitated easily. Other causes, such as heat and efflorescence, also contributed to the outcome of complex affinities, as was the case for natron. In short, elective affinity involved an unsaturated substance, while complex affinities worked between saturated substances. The notion of elective affinity was tightly bound to the analytic procedure in which two acids, one combined in the salt and the other free, had to compete for the common base. 

Effect of pH on the Partitioning of Acids and Bases in Octanol-Water... 

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