Question

a solution of 0.6216 g of an unknown solute in 50g of ccl4 yields a Bp of elevation of 0.647c find the molecular mass of the unknown solute if the molal elevation constant is 5.02k????​

Answer 1

Answer:

Napthlene C

10

H

8

,M=12×10+8=128g

Molality of Naphthalene in CCl

4

, m=

128

0.5

×

50

1000

ΔT

b

=K

b

m

0.4=K

b

128

0.5

×

50

1000

...(i)

Let the molar mass of unknown solute be M.

The molality of unknown solute in CCl

4

, m=

M

0.6

×

50

1000

ΔT

b

=K

b

m

0.65=K

b

×

M

0.6

×

50

1000

...(ii)

Divide equation (i) by (ii)

0.65

0.4

=

0.6×128

0.5×M

M=

0.65×0.5

0.4×0.6×128

=94.523