Intermolecular Forces in Binary Liquid Solutions: Refractive Index and Boiling Point Diagrams

Both the ways and extent that other molecules affect the clathrate structure of water are crucial to in vivo biological systems as well as in vitro experiments, but the intermolecular interactions between water and other molecules as well as many of the intricacies of water itself are not well understood. Using the method of refractive index to determine composition of binary solutions of small alcohols and water, boiling point diagrams were constructed for these systems. Since the boiling temperature of a solution reflects the extent of its intermolecular forces, boiling point diagrams can provide information regarding intermolecular interactions as composition of a binary liquid solution changes. In plotting raw refractive index data as well as molar refractive indices, the strong intermolecular forces and rearrangements of molecules relative to one another can also be characterized. In both this study and other related studies in our lab, including NMR analysis of proton environment and analysis of density, partial molar volume, and heat of mixing, there seems to be a trend involving the largest changes in measurable properties or largest deviations from ideality occurring at or around whole number stoichiometric ratios: 1:2, 1:1, and 2:1 specifically