Partial molar volumes and, viscosities of some transition metal sulphates in aqueous urea solutions

Abstract

Partial molar volume and viscosity data for cobalt(II), manganese(II) and iron(II) sulphates in urea-water mixtures (11.52, 20.31, 29.64 and 36.83 urea wt %) at different concentrations and temperatures are presented. The density data have been analysed using the Masson's equation. The limiting apparent molar volumes (<em>ϕ</em>_v^o) and the experimental slopes (<em>S</em>_v) have been interpreted in terms of solute-solvent and solute-solute interactions, respectively. The <em>ϕ</em>_v^o values vary with temperature as a power series of temperature. Structure making/breaking capacities of the transition metal sulphates have been inferred from the sign of (<em>∂²ϕ</em>_v^o/<em>∂</em>T²)_P. All the electrolytes behave as structure makers/promotors. The viscosity data have been analysed by means of Jones-Dole equation. The activation parameters have also been obtained on the basis of transition state theory in order to understand the mechanism of the viscous flow.