Molecular interactions analysis of some aluminium salts in binary aqueous solutions of tetrahydrofuran (THF): Acoustic and Conductometric approach

Abstract

Abstract In the present investigation conductance and speed of sound of aluminium sulphate, aluminium nitrate, and aluminium chloride were experimentally determined in aqueous medium as well in binary aqueous mixtures of THF. Various conductance and acoustic parameters viz; molar conductance, limiting molar conductance, partial molar adiabatic compressibility, coefficient of adiabatic compressibility were also determined using Kohlrausch's Law, Debye-Huckel theory and Masson’s equation at working temperatures and different compositions of THF. Analysis reveals that limiting molar conductivity ( Λ m 0 ) decreases with increase in composition of THF in water indicating the decrease in the ion-solvent interactions with increase in composition THF in water. Further it was found that with increase in temperature the Λ m 0 values increase for all the three salts which support the increase in ion-solvent interactions with increase in temperature. The values of partial molar isentropic compression ( ϕ K S 0 ) were found negative and these values further increase with increase in composition of THF indicating that on increase in composition, attractive interactions develop between THF and water which induces dehydration of aluminium salts which make the water molecules of aluminium salts more compressible than that of lower THF concentration resulting in decrease of ion solvent interactions with increase in THF composition in water. On the other hand with increase in temperature, the values of ϕ K S 0 further increase leading to increase in ion-solvent interactions of aluminium salts in water and 5% THF+ water. Walden product and its temperature coefficient i.e. [ d ( Λ m 0 η 0 ) ] have also been calculated which confirms that aluminium salts act as structure breaker in different compositions of THF in water.