What is meant by functional group ? Give examples.

Explanation

The compounds acquire specific chemical properties due to these hetero atoms or the groups of atoms that contain hetero atoms, irrespective of length and nature of the carbon chain in that compound. Therefore these hetero atoms or groups of atoms containing hetero atoms are called the functional groups.
Example : Methyl alcohol, acetic acid.
In methane `(CH_(4))`, when one hydrogen atom is replaced by an - OH group, group, methyl alcohol `(CH_(3)OH)`, is formed. The -OH is known as the alcoholic functional group.
Similarly, from methane `(CH_(4))` when one hydrogen atom is replaced by `-COOH` group, acetic acid `(CH_(3)COOH)` is formed. The `-COOH` group is known as the carboxylic acid functional group.