Electrical conductance of a mixture of sodium and potassium nitrates in aqueous medium

Abstract

Electrical conductance and density measurements of [xNaNO3 + (1 − x)KNO3] + RH2O system were taken as functions of x, R, and temperature. The mixed alkali effect on molar conductance (Λ) was found to be negligible upto R = 25 and becomes significant in the region where R < 25. It has been shown that for mixed electrolytic system in aqueous medium the concentration range at which the mixed alkali effect on Λ starts becoming significant can be predetermined by plotting the difference in Λ of the two pure electrolytic solutions versus R. The concentration dependence of Λ has been described satisfactorily by the expression Λ = ΛFLK exp (Bc + Cc2) where ΛFLK is the Falkenhagen–Leist–Kelbg equation for Λ, B and C are empirical constants, and c is the molar concentration. The observed values of the ion-size parameter have indicated more ionic association in KNO3 solution than in NaNO3 solution. Keywords: electrical conductance, sodium nitrate, potassium nitrate, mixed alkali effect.