Solutions of Symmetrical Strong Electrolytes at Moderate to High Concentrations

Conductivity of Solutions of Symmetrical Strong Electrolytes at Moderate to High Concentrations 

Here we consider the conductivity of strong electrolyte solutions at moderate to high concentrations in polar non-aqueous solvents. The conductivity of such solutions has been studied extensively, because of their importance in applied fields. 

If the conductivity of an electrolyte in a polar solvent is measured up to high concentrations, the conductivity-concentration relation usually shows a maximum as in Fig. 7.3. Such a relationship is explained by the competition between the increase in the number of charge carriers and the decrease in ionic mobilities, mainly due to the strengthening of ion-ion interactions. Various empirical equations have been reported to express such a relation. The Casteel-Amis equation [21] for the relation between k and the molal concentration m is 

Recently, Chagnes et al. [22] treated the molar conductivity of LiCl04 in y-buty-rolactone (y-BL) on the basis of the quasi-lattice theory. They showed that the molar conductivity can be expressed in the form A = (A°°) — fe c1/3 and confirmed it experimentally for 0.2 to 2 M LiCl04 in y-BL. They also showed, using 0.2 to 2 M LiCl04 in y-BL, that the relation k = Ac = (A°°) c — k cA was valid and that /cmax appeared at cmax = [3(xf00)74fe ]3 where d/c/dc=0. 

The concept of mean spherical approximation (MSA, 3) in Chapter 2) has also been used to reproduce the conductivity data of electrolytes of fairly high concentration [23]. The MSA method applies to both associated and non-associated electrolytes and can give the values of association constant, KA. Although not described here, 

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