Boiling Point Elevation

Boiling point elevation occurs when the boiling point of a solution becomes higher than the boiling point of a pure solvent. The temperature at which the solvent boils is increased by adding any non-volatile solute. A common example of boiling point elevation can be observed by adding salt to water. The boiling point of the water is increased.

Boiling point elevation, like freezing point depression, is a colligative property of matter. This means it depends on the number of particles present in a solution and not on the type of particles or their mass.

The amount of boiling point elevation can be calculated using the Clausius-Clapeyron equation and Raoult's law. For an ideal dilute solution:

Boiling Point_total = Boiling Point_solvent + ΔT_b

where ΔT_b = molality * K_b * i

with K_b = ebullioscopic constant (0.52°C kg/mol for water) and i = Van't Hoff factor