Temperature dependence of the electrical conductance and viscosity of nitrate—water mixtures, from fused salts to water

Abstract

It is shown that the specific electrical conductance χ and the equivalent electrical conductance Λ of some KNO 3LiNO 3H 2O and AgNO 3TlNO 3H 2O systems, at given compositions, from fused salts to water, over limited temperature ranges, are related to the molar volume V by equations similar to the Batschinski equation for fluidity: ▪ where V χ is the molar co-volume for the specific conductance, V Λ is the molar co-volume for the equivalent conductance, B χ and B Λ are other constants characteristic of the liquid mixtures. These parameters are discussed together with the parameters in Arrhenius type equations using such concepts as free volume and hole. At a given temperature, the fluidity φ and the equivalent conductance Λ may be expressed by the following equations ▪ with x the mole fraction, superscript ′ the apparent parameter and subscripts s, w and ∞, respectively, salt, water and salt at infinite dilution. The use of these equations leads to a remarkable observation with regard to the temperature dependence of φ and Λ. When the temperature is varied over a limited range, φ′ w and Λ′ ∞ are quasi-constant if, respectively, compared to φ w and Λ ∞. It is suggested that the apparent fluidity of water φ′ w is the fluidity of water linked to salt and containing hydrogen bounds highly perturbed by the electrostatic field of the ions. The apparent equivalent conductance at infinite dilution Λ′ ∞ is the equivalent conductance at infinite dilution in this special state of water.