Combustion Analysis


The analysis which is made to determine the amounts of different elements present in a compound by burning a known amount of organic compound containing C, H and O in the presence of oxygen is called” combustion analysis.”


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 bum the organic compound. Hydrogen is converted into H20 and carbon into CO2.

H2O absorber:

Next to combustion tube is H20 absorber. It contains Mg (ClO4) which absorbs H2O produced during the burning of organic compound.

CO2 absorber:

After H2O absorber chamber is CO2 absorber chamber. It contains 50% of KOH which absorbs CO2 produced during combustion analysis. The difference in the amounts or masses of these absorbers gives us the amounts of H2O and CO2

Combustion analysis


% of carbon = [mass of CO2 mass ÷ mass of organic compound] X [12/44] X 100

% of hydrogen = [mass of H2O ÷ mass of organic compound] X [2.016/18] X 100

The percentage of oxygen is obtained byjthe method of difference:

% of Oxygen = 100 – (% of carbon + % of hydrogen)

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