Molecular weight of glucose (C6H12O6)=180 ∴ Number of moles of glucose (nB)=18036=0.2
Molecular weight of water (H2O)=18 ∴ Number of moles of water (nA)=18176.4=9.8 ∴ Mole fraction of water (xH2O)=nA+nBnA =9.8+0.29.8 =109.8 ∵pH2O=xH2OpH2O∘ ∴pH2O=109.8×760=744.8 torr
(At boiling point of water, it vapour pressure is 1atm=760mmHg )