Density, viscosity and electrical conductivity of isobutyric acid-water with added ions in the critical regions

Density, viscosity and electrical conductivity of the six concentrated binary ionic mixtures of isobutyric acid-water with X M [KCl] at the critical concentrations were measured as functions of temperature (ΔT = T - Tc ≤ 2 K) and at various compositions, X, in the critical regions. The molar volumes have been calculated from their densities. The molar volume data dependence of viscosity and conductivity has been fitted to an equation similar to the Vogel-Tammann-Fulcher (VTF) based on the free volume model. The concentration of ions (K+, Cl-), dependence of the Vogel temperature, the intrinsic volume and the transport properties are primarily governed by the existence of intermolecular interactions.