Question

what is homologous series? write the name and draw the structure of the second member of alkene series.

Answer 1

Homologous series: It is a group of organic compounds which have similar structural and chemical properties.

The name of the second member of alkene is called as propene.

• Alkenes: It is a hydrocarbon containing a carbon-carbon double bond. The formula of alkene is $C_nH_{2n}$ where 'n' is the number of carbon atoms.
• Examples of alkenes: Methane, Ethane, Propane, etc.,
• Alkenes have similar structural and chemical properties hence they are called homologous series.
• Alkenes are usually found in unsaturated fats, beta-carotene. They are quite reactive as they have double carbon bonds present in them.

Answer 2

Homologous series is a series of organic compounds that have similar chemical properties and the same functional groups but they differ from the next member by an extra -CH₂ group.

• Alkenes have a double bond in their structure. The prefix for the alkene homologous series is -ene.
• The first member has two carbon atoms (a double bond requires the presence of at least 2 carbon atoms).
• The first member has the formula CH₂=CH₂. Its IUPAC name is ethene.
• The second member of the series is called propene. It has 3 carbon atoms and has the formula CH₃-CH=CH₂.