Transport Properties of Ions in Mixed Solvents

The conductivity of electrolytes and ionic limiting conductivities in mixed solvents are intimately related to the viscosities of these solutions according to the concept of the Walden product A°°t] = const for a given electrolyte (ion) irrespective of the temperature and the solvent or mixed solvent composition. 

The latter salt has a shallow minimum near explained by increasing 

The condnctivity of electrolytes in mixed solvents was recently reviewed by Apelblat [35] and only the main features are presented here. References to the data, for example those reported by Barthel and by Kay [36, 37], provide the limiting condnctivities A mainly, but not exclusively, for aqueous mixtures with cosolvents. It was shown by Apelblat [35] that the ratios of the A values (also the ionic values A, ) for different electrolytes (or ions) tend to universal values in the composition ranges rich in the one or the other solvent component of an A+B solvent mixture. At a given tanperature for any two electrolytes El and E2  

TABLE 6.4 Coefficients for Equation 6.4 for Aqueous Mixtures with Cosolvents at 25°C from Ref. 35, with the Presumed Standard Electrolyte El Noted 

For the corresponding coefficients a and b for some completely nonaqueous mixtures, the data by Kay [37] should be consulted. The concept of the universal conductivity curve according to Equation 6.3 was subsequently extended from the 1 1 electrolytes dealt with by Apelblat in Ref. 39 to multivalent electrolytes of the 1 2, 2 1, 2 2, 1 3, and 3 3 classes (examples being Na SO, MgCl, MnSO, and LaFe(CN)g)), tested in aqueous ethanol and 1,4-dioxane as well as in mixtures of methanol and ethylene glycol [39]. 

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