Mass of C: Mass of H=6:1.
Or, for every atom of C(12u), we have 2atoms of H(1u×2=2u)
Thus, the ratio of atoms of C:H=x:y=1:2
Thus, the formula is: CxH2xOz
Combustion of CxH2x:
CxH2x+(3x/2)O2→xCO2+xH2O
Hence, the combustion of CxH2x requires (3x/2) oxygen molecules.
Hence, the original molecule contains (3x/4)molecules =(3x/2)atoms.
Or, z=3x/2
Empirical Formula=CxH2xO3x/2=C2xH4xO3x=C2H4O3