Solvents, mixed aqueous acid/base properties

A great deal of experimental work has been carried out on acid-base equilibria in mixed solvents, especially mixtures of water with organic solvents. The presence of two solvent species introduces a number of complications. In the first place, there are now a number of different acidic and basic species derived from the solvent. Thus in aqueous alcohol we have as acids H2O, EtOH, H30, and EtOHj, and as bases H2O, EtOH, OH, and EtO". In the second place, the composition of the solvent can now vary in the neighbourhood of an ion (and to a smaller extent near an uncharged molecule) by a preferential solvation effect, so that the macroscopic properties of the solvent will be even less relevant than they are with pure solvents. For these reasons the problem of mixed solvents will not he discussed here. 

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