A chemist is given a 250 mL homogeneous solution that contains only three volatile organic compounds—hexane, ethyl acetate, and propan-1-ol. The table below summarizes relevant physical data collected at 1 atm.
Component
Normal boiling point (°C)
Relative polarity (qualitative)
Hexane
69
Very low
Ethyl acetate
77
Moderate
Propan-1-ol
97
High
The chemist must design a procedure that will deliver each compound in separate, pure (≥99 %) fractions while minimizing energy consumption.
(a) Determine the order in which the three components should be removed from the original mixture by distillation to minimize total energy input. Support your answer with quantitative or qualitative reasoning.
(b) After completing the distillation, trace impurities are detected in the propan-1-ol fraction. Identify the most probable impurity and explain why it co-distilled.
(c) Propose an additional separation technique that can be applied specifically to the contaminated propan-1-ol fraction to achieve the required 99 % purity. Explain how this technique relies on molecular-level interactions.