What is Homologous Series

Homologous Series is a collection of structurally and chemically identical organic compounds, where each member is distinguished from the others by a repeating unit. This functional group is called a repeating unit. At larger molecular sizes, the physical and chemical characteristics of these compounds often follow similar patterns and have the same basic formula. Carboxylic acids, alcohols, alkanes, alkenes, and alkynes are a few homologous series examples.

Formula for Homologous Series

A homologous series is a collection of organic compounds that have a general formula but are distinguished from one another by recurrent structural units. The following may be expressed as an equation:

General Formula: R – X

• R is Remainder of Molecule, or Main Carbon Chain
• X is Functional Group that establishes Series

In the alkane series, for instance, the usual formula is C_nH_2n+2. Every series member varies from the others by one CH₂ unit.

Homologous Series Definition

A homologous series consists of a of organic substances with comparable characteristics and structures and differ by a set of repeating group

Homologous Series is a family of organic compounds where two consecutive members in the family differ from each other by -CH₂ repeating unit. The mass difference between two such consecutive members is 14 units. They have same functional groups and show similar trends in physical and chemical properties.

This article deals with definitions, formulas, and examples of homologous series. A table discussing all the possible homologous series has been also added to the article. We have to study Homologous Series in Class 10 in the chapter on Carbon and its compound.