Biphenyl, C12H10, is a nonvolatile, nonionizing solute that is soluble in benzene, C6H6. At 25 °C, the vapor pressure of pure benzene is 100.84 torr. What is the vapor pressure of a solution made from dissolving 19.9 g of biphenyl in 34.3 g of benzene?

Answer 1

mols biphenyl = grams/molar mass.
mols benzene = grams/molar mass
Xbenzene = mols benzene/total mols.

pbenzene soln = Xbenzene*Ppure benzene solvent.