A Study of Solute-Solvent Interaction of Chloride and Bromide of Barium in Aqueous Dimethyl-formamide (DMF) between 298 and 313 K from Apparent Molal Volume Data.

Abstract

The apparent molal volume  φ_v of chloride and bromide of barium
in aqueous dimethyl-formarnide (DMF) of different compositions
(10, 20 and 40 wt %) with different concentrations of electrolytes
between 298 and 313 K have been determined from densities data.
The data have been analysed using Masson's equation. The limiting
apparent molal volumes (φ_v^o) and exprimental slopes (s_v*) have been
interpreted in terms of solute-solvent and solute-solute interactions
respectively. The  φ_v^o  values are found to be positive and increase
with the solvent compositions as well as with temperatures for both
the electrolytes.  The  φ_v^o values are higher for barium bromide while
S_v^* values are higher for barium chloride. s_v^*  values increase with
the rise in temperature and decrease with the increase in DMF in
the solvent.  φ_v^o  values for electrolytes are obtained by extrapolation
of curves for zero mole-fraction of DMF i.e. for water and they are
found to decrease with the rise of temperatures in case of barium
bromide.  The results have been correlated to the dielectric constant
of solvent and viscosity  β-coeffiecient of Jone-Dole equation. The
results are in good agreement to the conclusions proposed on the
basis of thermodynamic parameters of viscous flow obtained from
the method of Nightingale and Benck.