Question

A solution is separated from pure solvent by a semipermeable membrane at 298 K. The difference in the height of the solution and the solvent is 0.9 m. If `K_(f)` and freezing point of the solvent are `30 K kg mol^(-1)` and 250.3 K, respectively, the temperature which the solution freezes is :
(Assume density of solution be 1 g/cc)
A. 250.10 K
B. 250.25 K
C. 250.20 K
D. 250.05 K

Answer 1

Correct Answer - C
`pixx13.6xxgxx76=90xxgxx1`
`pi=0.087` atm
`pi=CRT`
`0.087=Cxx0.082xx298`
`C=3.56xx10^(-3)M`
`DeltaT=K_(f)xxm=30xx3.56xx10^(-3)~= 0.1`
`:.` Freezing point of solution will be : `250.3 - 0.1 = 250.2 K`]