Question

Arrange the following solutions in order of increasing freezing point depression. [Hint: The corresponding van’t Hoff factor (i) is given]:
(a) 0.10 m MgCl2 in water, i = 2.7, Kf = 1.86°C/m for the solvent (water).
(b) 0.20 m toluene in diethyl ether, i = 1.00, Kf = 1.79°C/m for the solvent (diethyl ether).
(c) 0.20 m ethylene glycol in ethanol, i = 1.00, Kf = 1.99°C/m for the solvent (ethanol).

Answer 1

hy we know that: At ikfm -10 where AT= freezing point depression i= van't Hoff factor Kf = freezing point depression constant m= molality (9) given: m=0.10m Ÿ = 2.7 kg = 1.86°c/m substituting the values in eqn(1), AT= 2.7 * 1.86°4m x 0.1om = 0.5022°C = 0.502°C (6) given m=0.20m i = 1:00 Kf = 1.79€/m Substituting the values in ean.(1), 071100x1.7994m x0.20m = 0.358°C

given: m=0.20m i=1.00 Kf = 1.99°/m Substituting the values in ean.1, AT= 1.00x1.99°Cmx0.20m = 0.398°C The cader is given by: (6) <3<@