Freezing Point Depression
The lowering of a solvent's freezing point caused by dissolved solute particles.
Formula / equation
ΔT_f = i K_f m
Unit
°C
In depth
Solute particles are excluded from the growing crystal lattice and lower the chemical potential of the liquid solvent, so a lower temperature is required before solid and liquid are in equilibrium. Since K_f values are larger than K_b values, cryoscopy is generally the more sensitive technique.
Examples in the real world
Rock salt lowering the melting point of ice on roads; glycerol protecting frozen biological samples.