Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.

Explanation

The series of organic compounds having same functional group and similar chemical properties is called homologous series.
Each member differs from successive member by - `CH_(2) `- group. The difference in molecular weigth between two successive members is 14 u.
Characteristics. :
It has same general formula, from which all members can be derived.
(ii) They have similar chemical properties.
`C_(2)H_(4), CH_(2) = CH_(2)` , Ethene is first member of alkene series.