A Study of Hydrogen Bonding Using Liquid–Vapor Equilibria

Many undergraduate laboratories use the familiar liquid–vapor equilibrium experiment to demonstrate the Clausius–Clapeyron equation. This paper aims to extend this experiment beyond typical liquid–vapor equilibrium calculations to also explore the hydrogen-bonding capabilities of a series of liquids. By carefully choosing a series of liquids that are very close in molecular weight, but very different in composition (an amine, an alcohol, and a hydrocarbon), students will be able to observe the importance of hydrogen bonding on thermodynamic properties, such as the entropy and enthalpy of vaporization and the normal boiling point of a liquid, and they will be able to verify the assumptions made by Trouton’s rule. Using these chosen liquids, many chemical principles can be explored concurrently with the normal liquid–vapor equilibrium experiment.