What is a homologous series? Explain with an example .

Explanation

Homologous series is a series of compounds with the same functional group and similar chemical properties in which each successive member differs by `CH_2`. This can be along the length of a carbon chain.
The homologous series of straight chained alkenes begins with methane `[CH_4]`, ethene `[C_2H_6]`, propane `[C_3H_8]` butane `[C_4H_10]` and pentane `[C_2H_12]` in this series , successive members differ in mass by an extra methylene bridge `[-CH_2-`unit ] inserted in the chain . Thus the molecular mass of each member differs by 14 atomic mass units . Adjacent members in such a series , such as methane and ethane, are known as " adjacent homologues. "