The concept of Frank’s hypothesis (that is the effect of large tetra alkyl ammonium ions on the solvent structure, especially water, in the ion-ion and ion-solvent interactions) was found to be not applicable when water was replaced by one of the organic solvents e.g. Dimethyl formamide (DMF), in the solvent mixture, that is, if the study involves ion-ion and ion- solvent interactions in 1,5-pentane diol-DMF solvent mixture containing large cations of tetraalkyl ammonium iodides. The densities of binary solvent mixtures and salt solutions have been measured at 298.15 K by magnetic float densitometer. The apparent molar volumes at infinite dilution, ΦV0 determined by ΦV –values in the solvent mixtures, have been utilized to estimate the partial molar volumes of transfer, ΔΦV0(tr), for various tetraalkyl ammonium iodide salts from DMF to 1,5-Pentane diol.
Ion - solvent Interactions, 1, 5-Pentane diol- DMF mixtures