Question

Raoult's Law: The common laboratory solvent water is often used to purify substances dissolved in it. The vapor pressure of water is 23.76 mm Hg at 25

Answer 1

according to Roult's law

P _solution = X _solvent P_solvent

let the molecular weight of the compound = M

moles of the compound present in the solution = 130.7 / M

moles of water = 275.0 / 18.02 = 15.26

mole fraction of water = moles of water/ total moles = 15.26 / (15.26 + 130.7/M)

vapour pressure of the solution (P _solution)= 23.18 mm of Hg

vapour pressure of the solution (P _solvent) = 23.76 mm of Hg

23.18= 15.26 / (15.26 + 130.7/M)   x23.76

M = 348.53 mm of Hg

Molecular weight of the compound = 348.53 mm of Hg