The Conductance and Ionic Mobilities for Aqueous Solutions of Potassium and Sodium Chloride at Temperatures from 15° to 45°C

Abstract

The conductance of aqueous solutions of potassium and sodium chloride has been determined at 15, 25, 35 and 45°C for concentrations from 0.0005N to 0.01N by a modified direct-current method of high precision. At 15° and 25°, the results are in highly satisfactory agreement with the best of the existing data obtained by the a.c. bridge method. For all temperatures, the conductance can be represented within a few hundredths of a percent by the extended Onsager-Shedlovsky equation. A calculation of the mobility of chloride ion from the conductance and the transference numbers obtained in this laboratory shows that for all temperatures the Kohlrausch rule of independent ionic mobilities is obeyed at infinite dilution within the apparent limit of error of the measurements—0.02 to 0.03 percent. The conductance and ionic mobilities for round values of the concentration, and the temperature coefficients of the ionic mobilities at infinite dilution are tabulated.