Boiling Point Elevation
The rise in a solvent's boiling point caused by the presence of a non-volatile solute.
Formula / equation
ΔT_b = i K_b m
Unit
°C
In depth
Because the solute lowers vapour pressure, a higher temperature is needed before the vapour pressure reaches atmospheric. The elevation is proportional to molality and to the van't Hoff factor, so it depends only on particle count and provides a route to molar mass called ebullioscopy.
Examples in the real world
Adding 1 mol of sugar to 1 kg of water raises the boiling point by 0.512 °C; 1 mol of NaCl raises it about 1.02 °C.