Define cryoscopic constant

Cryoscopic constant (K_f): The cryoscopic constant is defined as the depression in the freezing point of a solvent caused when 1 mole of a non-volatile solute is dissolved in 1 kilogram of the solvent.

Expression:

K_f = (ΔT_f × M) / (1000 × m)

• ΔT_f = depression in freezing point
• M = molar mass of solute
• m = mass of solute (g)

Unit of Cryoscopic Constant:

K_f = K·kg·mol⁻¹

(Kelvin kilogram per mole)

Final Answer: The cryoscopic constant (K_f) is the depression in freezing point of a solvent produced by dissolving 1 mole of solute in 1 kg of solvent.