The general formula of the alkanes is C_n H_ 2n 2. They differ from each other by the number of CH 2 units in the main carbon chain. The two adjacent homologues have a difference of molecular mass of 14 u i All the members of a homologous series can be represented by the same-general formula.
They are insoluble in water.
The general molecular formula for carboxylic acids is C n H 2n1 COOH. Therefore the general formula for the homologous series of alkanes is C2H2n2. Two consecutive members of a homologous series differs each other in their composition by CH 2 unit. The members of this series are called homologues.