The Temperature Coefficient of the Conductance of Potassium Chloride in H2O—D2O Mixtures

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Abstract
The temperature dependence of the equivalent conductance Λ of 0.02 molar potassium chloride has been studied at 5, 25, and 45°C as a function of the deuterium content of the solvent. The new data for Λ at 5 and 45°C exhibit the same sag type of curve when plotted against the deuterium fraction, FD, of the solvent as observed previously by LaMer and Baker for 0.01M KCl at 25°C. Although the equivalent conductance in pure D2O decreases to 83 percent of the H2O value, the Walden product (Λη) of equivalent conductance Λ multiplied by relative viscosity of the solvent η remains almost constant. It increases slightly but linearly with FD from 138.5 to 141.1 at 25°C. Similar behavior is noted at 5° and 35°C. The temperature coefficients of conductance (1/Λ)(ΔΛ/Δt) for the intervals 5–25° and 25–45°C increase linearly and in parallel with FD corresponding to 8.1 percent and 5.7 percent respectively on passing from H2O to D2O.