Which laboratory process separates components of a liquid mixture based on differences in boiling points?

• A. Filtration
• B. Chromatography
• C. Evaporation
• D. Distillation

Answer: (D)

This question tests the idea of separating liquids by differences in how easily they vaporize. When a mixture is heated, the component with the lower boiling point tends to turn into vapor first. That vapor can be captured and cooled back into a liquid in a separate container, leaving the higher-boiling components behind. This is distillation. If two liquids have similar boiling points, a fractionating column provides many tiny vaporization-condensation cycles to improve the separation. Other methods don’t rely on boiling point differences: filtration removes solid particles, chromatography separates substances by how they interact with a stationary phase, and evaporation by itself typically removes a solvent without separating multiple liquid components by their boiling points in a controlled, collectible way.