Empirical Formula From Combustion Analysis:
Combustion analysis is also called as elemental analysis. It is used for qualitative and quantitative analysis of hydrocarbons or organic compounds containing C, H and O only.
Combustion analysis is used to find out the percentage composition of an organic compound by combusting it in excess supply of oxygen.
Experiment:
A weighed sample of the organic compound is placed in the combustion tube. This combustion tube is fitted in a furnace. Oxygen is supplied to burn the compound. Hydrogen is converted to H2O and carbon is converted to CO2. These gases are absorbed in Mg (CIO4)2 and 50% KOH respectively.

Amount of CO2 and H2O
• The difference in the masses of these absorbers gives us the amounts of H2O and CO2 produced.
• The amount of oxygen is determined by the method of difference.
Calculations
(i) % Hydrogen
(ii) % Carbon
(iii) % Oxygen = 100 – (% of C + % of H) ———– method of difference.