Effect of Electrolyte Concentration on Solution Conductivity

It has been seen that reliable conductivity values are known only at low electrolyte concentrations. Under these conditions, even conductance equations for models such as the McMillan-Mayer theory (Sections 3.12 and 3.16) are known. However, the empirical extension of these equations to high concentration ranges has not been successful. One of the reasons is that conductivity measurements in nonaqueous solutions are still quite crude and literature values for a given system may vary by as much as 50% (doubtless due to purification problems). 

One characteristic of conductivity curves when studied in a wide concentration range is the appearance of maxima, as shown in Fig. 4.102. These maxima are always observed when the solubility of the electrolyte in the given solvent is sufficiently high. They are the result of the competition between the increase of conductivity due to the 

Another type of behavior observed when plotting conductivities versus c is the presence of temperature-dependent minima and maxima, as shown in Fig. 4.104. This unusual behavior has been attributed to triplet-ion formation (see Section 4.8.11). In this case Walden s rule (Section 4.4.12) has been used to calculate the values of equivalent conductivities at infinite dilution A°. 

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