Effect of Temperature on the Ion‐Solvent Interactions in Water‐Urea Mixtures from Volume Data

Abstract

Densities of solutions of NaCl, NaI, KCl, KBr, and CsCl in three mixtures containing 10 wt% (3.22 mol%), 20 wt% (6.98 mol%) and 30 wt% (11.39 mol%) urea in water have been measured at 333.15 K using the magnetic float densitometer. The apparent molal volumes of the electrolytes calculated from the experimental data were extrapolated to infinite dilution by means of the Masson equation. The ionic partial molal volumes of alkali‐metal and halide ions have been estimated. The partial molal volumes of transfer of ions from water to water‐urea mixtures were separated into the two components: V̄0elect(tr) and V̄0disord(tr). The effect of urea and temperature on V̄0elect(tr) and V̄0disord(tr) in the temperature range 298.15–333.15 K is discussed.