In a fractionating column, the highest-boiling components tend to
reach the condenser first and are collected first
condense lower down and drip back into the flask
condense near the top of the column
boil first because they have the most energy
107 exam-style questions on Edexcel GCSE Chemistry 3.2 Methods of separating and purifying substances, covering 3.2.1 Pure substances and mixtures, 3.2.2 Techniques for separating mixtures, 3.2.3 Paper chromatography and Rf values, and 3.2.4 Making water potable. Each one has a worked solution and a mark scheme showing where the marks go.