Given, empirical formula of compound =C2H5O Vapour density =45 Molecular formula = ? Empirical formulas show the simplest whole number ratio of atoms in a compound. Molecular formula show the number of each type of atom in a molecule. Relation between empirical formula and molecular formula. Molecular formula =n (empirical formula)
n=
MM (molar mass)
EFM (empirical formula molar mass)
Molecular weight =2× vapour density =2×45=90 Let, the molecular formula be C2xH5xOx. Therefore,