Question

A dilute solution of bromine in carbon tetrachloride behaves as an ideal-dilute solution. The vapour pressure of pure CCl4 is 33.85 Torr at 298K. The Henry’s law constant when the concentration of Br2 is expressed as a mole fraction is 122.36 Torr. Calculate the vapour pressure of each component, the total pressure, and the composition of the vapour phase when the mole fraction of Br2 is 0.050, on the assumption that the conditions of the ideal-dilute solution are satisfied at this condition

Answer 1

Explanation:

The given data is as follows.

     Vapour pressure of pure $CCl_{4}$ = 33.85 Torr

         Temperature = 298 K

      Mole fraction of $Br_{2}$ = 122.36 torr

Therefore, calculate the vapor pressure of $Br_{2}$ as follows.      

     Vapour pressure of $Br_{2}$ = mole fraction of $Br_{2}$ x K of $Br_{2}$

                                    = 0.050 x 122.36 Torr

                                   = 6.118 Torr

So, vapor pressure of $Br_{2}$ is 6.118 Torr .

Now, calculate the vapor pressure of carbon tetrachloride as follows.

     Vapour pressure of $CCl_{4}$ = mole fraction of $CCl_{4}$ x Pressure of $CCl_{4}$

                                     = (1 - 0.050) × 33.85 Torr

                                     = 32.1575 Torr

So, vapor pressure of $CCl_{4}$ is 32.1575 Torr  .

Hence, the total pressure will be as follows.

                         = 6.118 Torr + 32.1575 Torr

                         = 38.2755 Torr

Therefore, composition of $CCl_{4}$ = $\frac{32.1575 Torr}{38.2755 Torr}$

                         = 0.8405

Composition of $CCl_{4}$ is 0.8405 .

And, composition of $Br_{2}$ = $\frac{6.118 Torr}{38.2755 Torr}$

                                                  = 0.1598

Composition of $Br_{2}$ is 0.1598 .