Answer:
VP(solution) = 186.3 Torr
Explanation:
Given 24g Lactose (C₁₂H₂₂O₁₁) IN 200g H₂O @338K (65°C) & 187.5Torr
VP(soln) = VP(solvent) - [mole fraction of solute(X)·VP(solvent)] => Raoult's Law
VP(H₂O)@65°C&187.5Torr = 187.5Torr
moles Lactose = (24g/342.3g/mol) = 0.0701mole Lactose
moles Water = (200g/18g/mol) = 11.11mole Water
Total moles = (11.11 + 0.0701)mole = 11.181mole
mole fraction Lac = n(lac)/[n(lac) + n(H₂O)] = (0.0701/11.181) = 6.27 x 10⁻³
VP(solution) = 187.5Torr - (6.27 x 10⁻³)187.5Torr = 186.3Torr
