i) Molal elevation constant is defined as the elevation in boiling point produced when 1 mole of solute is dissolved in one kg (1000 g) of the solvent. It is also known as the ebullioscopic constant.
ii) The freezing point depression (ATf) of solutions of nonelectrolytes has been found to be equal to the molality (m) of the solute times a proportionality constant called the molal freezing point depression constant
(Kf). ... ATf = Kf × m, where m is the number of moles of solute per kilograms of solvent.
It is also known as the cryoscopic constant