510 mg of liquid on vaporization in Victor Meyer's apparatus displaces 67.2  cm3 of air at (STP). The molecular weight of the liquid is _____

Number of moles of air displaced by liquid = vol of air displaced22.4lit.=67.2×10-322.4=3×10-3molesMolecular weight of  liquid = Wt.no.of moles=510×10-3g3×10-3=170g   (since n=wt.mol.wt.)