The empirical formula of a compound is CH2. One mole of this compound has a mass of 42 g. lts molecular formula is

Weight of empirical formula,CH2=12+(1×2)=12+2=14Mass of one mole of the compound = its molecular weight                                                      = 42n= Mol. wt.  Empirical formula wt. =4214=3∴  Mol. formula =( empirical formula )×n=CH2×3=C3H6