Boiling Point Elevation Calculator

Boiling point elevation is the rise in a solvent's boiling point when a nonvolatile solute is dissolved in it. Like freezing point depression, it is a colligative property that depends on the number of dissolved particles, not their chemical identity. Salted water boils at a slightly higher temperature than pure water.

Delta Tb = i * Kb * m, where i is the van 't Hoff factor (particles per formula unit), Kb is the ebullioscopic (molal boiling point elevation) constant of the solvent, and m is the molality in moles of solute per kilogram of solvent. The new boiling point is the pure solvent boiling point plus Delta Tb.

Kb is a solvent property giving the boiling point rise per unit molality. For water it is about 0.512 degrees C per molal; for benzene it is about 2.53 degrees C per molal. It is a user-editable input here so you can enter the value for your specific solvent from a reference table.

Adding a typical pinch of salt to a pot of water raises the boiling point by only a fraction of a degree. To raise it by even one degree Celsius you would need roughly a 1 molal sodium chloride solution (about 58 grams of salt per kilogram of water with a van 't Hoff factor of 2), far more than normal seasoning.

Molality is in moles of solute per kilogram of solvent, Kb is in degrees C per molal, and the van 't Hoff factor is dimensionless. The boiling point elevation Delta Tb and the resulting new boiling point are in degrees Celsius. The pure solvent boiling point defaults to 100 degrees C for water at one atmosphere.