Fractional distillation separates components based on boiling points. Which compound is recovered first when the following boiling points are considered: Dichloromethane 39.6°C, n-hexane 68°C, Xylene 140°C?

• A. n-hexane
• B. Dichloromethane
• C. Xylene
• D. All of the above

Answer: (B)

In fractional distillation, the component with the lowest boiling point is the most volatile and will vaporize first, so it is collected first as the distillate. Here, dichloromethane boils at 39.6°C, which is lower than n-hexane at 68°C and xylene at 140°C. As you gently heat, dichloromethane becomes the vapor first and travels up the column to condense in the receiver, while the higher-boiling components stay in the liquid phase longer and distill later. So dichloromethane is recovered first.