Boiling Point Elevation Calculator

Your details

Switch modes to reverse-solve for any variable in ΔTb = i·Kb·m.
Choosing a solvent auto-fills its Kb and normal boiling point.
Auto-filled from the solvent preset. Override for a custom solvent or literature value.
°C·kg/mol
Picks a realistic effective van 't Hoff factor. Real electrolytes are slightly below the ideal integer due to ion pairing.
Number of particles per formula unit in solution. Auto-filled by solute preset; adjust for real solutions where ion pairing lowers the effective i.
Moles of solute per kilogram of solvent. Use the mass-to-molality section below if you prefer to enter masses.
mol/kg
Auto-filled from the solvent preset (100 °C for water). Used to compute the solution boiling point.
°C
Enter solute and solvent masses plus the molar mass of the solute instead of typing molality directly.
Applies to the boiling point elevation and solution boiling point outputs.
Boiling point elevation (ΔTb)
0.9728

Temperature rise due to dissolved solute

Solution boiling point100.97
Molality (m)1mol/kg
Van 't Hoff factor (i)1.9
Ebullioscopic constant (Kb)0.512°C·kg/mol
Molality (mol/kg)1
Van 't Hoff factor1.9
Kb (°C·kg/mol)0.512

ΔTb = 0.973 °C, so the solution boils near 100.97 °C.

  • The solution boils about 0.973 °C higher than the pure solvent.
  • An effective van 't Hoff factor of 1.9 shows the solute breaks into multiple particles in solution, multiplying the colligative effect.
  • Boiling point elevation is colligative: the identity of the solute does not matter, only the number of particles it releases.

Next stepThe same dissolved particles also depress the freezing point. Try the freezing point depression calculator (ΔTf = i·Kf·m) to find both colligative effects at once.

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