Which of the following is NOT typically considered a type of distillation?

• A. Simple distillation
• B. Fractional distillation
• C. Vacuum distillation
• D. Filtration

Answer: (D)

Distillation relies on vaporization and condensation to separate components with different boiling points. Simple distillation heats a liquid until a portion boils and recondenses to separate a volatile component from a less volatile one. Fractional distillation adds a fractionating column to improve separation when boiling points are close, using repeated vaporization-condensation cycles. Vacuum distillation lowers the ambient pressure so components boil at lower temperatures, which helps with heat-sensitive mixtures. Filtration, in contrast, is a separation method based on particle size or solubility and does not involve changing a substance from liquid to vapor. It removes solids from liquids (or separates a solid from a liquid) through a barrier or adsorption, not by vaporizing components. Hence filtration is not typically considered a type of distillation.