An aqueous solution containing 0.2 g of a non volatile solute 'A' in 21.5 g of water freezes at 272.814 K. If the freezing point of water is 273.16 K, the molar mass (in g mol ⁻¹ ) of solute A is [ K _ f ( H ₂ O )=1.86 ~K ~kg ~mol ⁻¹ ]