What is the vapor pressure of the pure solvent if the vapor pressure of a solution of 10 g of sucrose (c6h12o6) in 100 g of ethanol (c2h6o) is 55 mmhg?

Explanation:

The given data is as follows.

Vapor pressure of the solution = 55 mm Hg

Mass of sucrose = 10 g

Molar mass of sucrose = 180 g/mol

Therefore, moles of sucrose present into the solution will be calculated as follows.

             No. of moles =

                                   =

                                   = 0.055 mol

Mass of ethanol is given as 100 g and its molar mass is 46 g/mol.

Hence, number of moles of ethanol will be calculated as follows.

            No. of moles =

                                  =

                                  = 2.174 mol

As mole fraction =

Hence, mole fraction of etahnol will be calculated as follows.

            =

                                              =

                                              = 0.975

Now, using Raoult's Law  as follows.

              =

                                    =

                                    = 56.4 mm Hg

Thus, we can conclude that the vapor pressure of the pure solvent is 56.4 mm Hg.