Question

A solution of urea boils at 100.78 degree Celsius at the atmospheric pressure. If Kf and Kb for water are 1.86 and 0.512Kkgmol respectvaly then the above solution will freeze at

Answer 1

Answer:

️

Given : Boiling point of solution =100.18

o

C

K

b

=0.512Kkgmol

−1

K

f

=1.86Kkgmol

−1

ΔT Boiling =100.18

o

−100

o

=0.18

ΔT=K

b

×molality

∴ molality =

0.512

0.18

Now, ΔT

freezing

=K

f

×molality

=1.86×

0.512

0.18

=0.6539

∴ Freezing point of solution =0−0.6539

o

C

=−0.6539

o

C