The vapour pressure of pure benzene is 639.7 mm Hg and the vapour pressure of solution of a solute in benzene at the temperature is 631.9 mm Hg. Calculate the molality of the solution.
Calculate mole fraction of solute from Relative lowering of vapour pressure then divide mole fraction of solute by mole fraction of solvent
U will get the ratio of moles then adjust the factors to get molality
1038.04m since vapour pressure of soln.p1=v.p of c6h6*mole fraction of solute(x1)........& m=(1000(x1))/M.wt of c6h6*x2)