A Homologous Series is a group of organic compounds having the same functional group and similar chemical properties.

• Successive members differ by a Methylene group ($-C{H}_2-$) unit.
• This difference leads to a difference in molecular mass of $14\text{ u}$ ($12+2\times 1$).
• Regular progression in physical properties (like boiling point) is observed as the chain length increases within the series.