1 kg of 0 . 75 molal aqueous solution of sucrose can be cooled up to - 4 ° C before freezing. The amount of ice (in g ) that will be separated out is ___________. (Nearest integer) [Given : K f H 2 O = 1 . 86 K kg mol - 1 ]

Step-by-step solution

Let mass of water initially present = xg Mass of sucrose = ( 1000 - x ) g Number of moles sucrose = 1000 - x 342 Molality M = 1000 - x 342 x / 1000 = 0 . 75 2565 . 5 x = 10 6 - 1000 x x = 795 . 86   g no. of moles of sucrose = 0 . 5969 ΔT f = ik f   m 4 = 1 × 1 . 86 × 0 . 5969 ( 795 . 86 - a ) g × 1000 Ice separated = 518 . 3   g