What Is Boiling Point Elevation?

A boiling point elevation calculator uses the colligative property that governs how solutes raise the boiling temperature of a solvent. When a non-volatile solute dissolves, it lowers the solvent's vapor pressure, so a higher temperature is required for the solution's vapor pressure to reach atmospheric pressure and boil.

The Formula

ΔTb = i × Kb × m. The elevation equals the van't Hoff factor multiplied by the solvent's ebullioscopic constant (Kb) and the molality of the solution. Because it is a colligative property, the effect depends only on particle count — 0.5 mol of any non-electrolyte in 1 kg of water raises the boiling point by the same amount.

Common Solvent Constants

Water has Kb = 0.512 °C·kg/mol and boils at 100 °C; ethanol Kb = 1.22; benzene Kb = 2.53; chloroform Kb = 3.63; carbon tetrachloride Kb = 5.03. The calculator includes these values so you only need to enter solute amount, solvent mass, and the van't Hoff factor.