Question

Ex When 200 gram of
compound is dissolved in
250 gram ,
Bensene (solvent)
to make 1 molas solution
calculate molar mass of
that compound.​

Answer 1

Answer:

Let W g of compound is to be dissolved.

Number of moles of compound, n=

molar mass

mass

=

256

W

Mass of benzene = 75 g =

1000

75

kg=0.075kg

Molality of solution, m=

mass of solvent in kg

number of moles of solute

m=

256×0.075

W

=

19.2

W

m

The depression in the freezing point, ΔT

f

=0.48K

The molal depression in freezing point constant =K

f

=5.12Kkg/mol

ΔT

f

=K

f

m

0.48=5.12×

19.2

W

W=

5.12

0.48×19.2

=1.8

Hence, 1.8 g of solute is to be dissolved

hope it help u✨