What is boiling point elevation?

The term boiling point elevation refers to solutions having higher boiling points than pure solvents. Boiling point elevation is a colligative property of a solution.

Boiling point elevation is not dependent on the type of solute (dissolved particles), but rather on their number (concentration). Suspended particles “dilute” the solvent, causing a drop in the solvent’s vapor pressure. Since liquids boil when their vapor pressure is equal to atmospheric pressure, diluted solvents need a higher temperature to reach that point.

Correspondingly, diluted solvents also have decreased freezing points. This colligative property is successfully utilized in the winter, when adding antifreeze to a car’s cooling system prevents freezing of the system despite temperatures below water’s normal freezing point.