A solution is made by dissolving 20 g of a solute (molar mass = 40 g/mol) in water. If the freezing point depression is
Moles = (20/40) = 0.5 . Δ Tf = Kf · m . 0.465 = 1.86 × (0.5/w) , w = (0.5 × 1.86/0.465) ≈ 2 kg = 2000 g . Total mass = 20 + 2000 = 2020 g .
Ref: NCERT Class 12 Chemistry > Chapter 1: Solutions > Topic: Colligative Properties - Depression of Freezing Point