What method is used to separate liquids based on their boiling points?

The method used to separate liquids based on their boiling points is fractional distillation. This technique is particularly effective when separating a mixture of liquids that have closer boiling points. During fractional distillation, the mixture is heated, and the component with the lower boiling point vaporizes first. The vapor then travels up the fractionating column, where it cools and condenses back into a liquid at different heights depending on its boiling point.

The process allows for the gradual separation of the components as they are collected, ensuring a high degree of purity. This is especially useful in industries for the separation of petrochemical products, alcoholic beverages, and other solutions where multiple components are present in various quantities.

In contrast, methods like filtration are used for separating solid particles from liquids or gases, while evaporation simply removes a liquid by converting it into vapor, leaving solids behind. Simple distillation is used when there is a significant difference in boiling points but is less effective than fractional distillation for more closely boiling components.