Molecules acid/base properties uncharged

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. 

The cosolvent will lower the dielectric constant of the mixed solvent, independent of the properties of the solute molecule. The ionization constant of acids will increase and that of bases will decrease (see Sections 3.3.3 and 3.3.4), the result of which is to increase the fraction of uncharged substance in... 

The above considerations led us to the conclusion that the use of equation (1.3.6), as a rule, yields appreciably distorted fl values which, in their turn, complicate the estimations of molten salt acidity. One of the pro reasons is the fact that the use of this equilibrium implies [Cl-] = constant. This is true for the case of the melts based on alkali chloride melts—among them chloride-sulfate and chloride-nitrate melts—should be mentioned. However, reaction (1.3.6) cannot be used for estimating the acidic properties of melts without chloride ions. Besides, neutral (uncharged) HC1 and H20 molecules are foreign admixtures for ionic melts as ionic substances in aqueous medium in both cases, there are two kinds of principally different interactions electrostatic (between ions) and Van der Waals or donor-acceptor interactions (between uncharged particles). 

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