Principle

A boiling point diagram shows the boiling points of a binary mixture as a function of the vapour / liquid equilibrium of the mixture at constant pressure. The boiling points of various mixtures of methanol and chloroform are measured and the composition of the liquid phases are determined using refractometry and a calibration curve.

Benefits

• Important basic experiment for distillation
• Excellent for the introduction of refractometry

Tasks

1. Determine the refractive indices of the pure components and about 10 different mixtures of known composition.
2. Plot the boiling point diagram of the binary mixtures of methanol and chloroform.

Learning objectives

• Fundamentals of distillation
• Equilibrium diagram
• Chemical potential
• Activity coefficient
• Raoult's law

Additional necessary

• Chloroform