J.R. S. answered 02/06/23
Ph.D. University Professor with 10+ years Tutoring Experience
Raoults law and Daltons law of partial pressure
moles H2O = 460.0 ml x 1 g / ml = 460 g x 1 mol / 18 g = 25.56 mols
moles glucose = 218.2 g x 1 mol / 180.16 g = 1.211 mols
Total moles = 26.77 moles
Mole fraction water (XH2O) = 25.56 / 26.77 = 0.9548
Vapor pressure of solution = 0.9548 x 31.8 torr = 30.4 torr
Vapor pressure lowering = 1.4 torr