Chemical Properties of Alkane


  • Combustion
    • Combustion of alkane involves the reaction of alkane with oxygen gas in the air.
    • Complete combustion of an alkane is when the oxygen gas is in excess.
    • The products of complete combustion of alkane are carbon dioxide gas and water.
    • Example of the complete combustion of methane;
\(CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l)\)


    • In the case of insufficiency of oxygen gas, the incomplete combustion of alkane occurs.
    • The products such as carbon monoxide and carbon might be formed from incomplete combustion of alkane.
    • Example of the incomplete combustion of methane;

\(2CH_4(g) + 3O_2(g) \rightarrow C(s)+CO_2(g) + 4H_2O(l)\)


\(6CH_4(g) + 9O_2(g) \rightarrow 2C(s)+2CO(g)+2CO_2(g) + 12H_2O(l)\)


  • Substitution reaction
    • A chemical reaction where another atom is substituting one or more atoms in a molecule.
    • The substitution reaction of alkane that involves halogen is also called a halogenation reaction.
    • The sunlight is needed in this reaction.
    • The energy from the sunlight is needed to break the covalent bond in the halogen compound to form bond with halogen atoms.
    • Example of substitution reaction of methane with chlorine;
\(CH_4(g) + Cl_2(g) \rightarrow CH_2Cl_2(l) + H_2(g)\)