Electrical Conductivity, Viscosity and Molar Volume of Potassium Nitrate–Sodium Nitrate in Cadmium Nitrate Tetrahydrate Melt

Abstract

The electrical conductivities, viscosities and molar volumes of the 0·3[xKNO₃+(1 – x)NaNO₃]+ 0·7Cd(NO₃)₂.4·4H₂O systems were measured as functions of temperature (293·15 ≤ T/K ≤ 363·15) and composition (x = 0·0 to 1·0 mole fraction). The temperature dependence of the electrical conductivity and viscosity was non-Arrhenius in nature and has been analysed by using the Vogel–Tammann–Fulcher (VTF) equation. Both conductivity and viscosity vary non-linearly with the molar volume and have been explained by using VTF-type equations based on the free volume model. In the present system the molar volume and the intrinsic volume are additive. A significant mixed alkali effect has been observed in the normalized electrical conductivity and viscosity and in the electrical conductivity at the isofluidity condition. The variation of the electrical conductivity is governed by the mobility of the potassium ions. The onset of the mixed alkali effect has been explained by the anion polarization model.