Final answer:
Alkanes have no functional groups, alkenes have a carbon-carbon double bond, alcohols have a hydroxyl group, and amines have a nitrogen atom as the functional group.
Step-by-step explanation:
In organic chemistry, functional groups are specific groups of atoms within a molecule that determine its reactivity and chemical properties. Let's identify the functional groups in the given molecules:
a. Alkane - Alkanes are hydrocarbons with only single bonds. They have no functional groups.
b. Alkene - Alkenes have a carbon-carbon double bond. The functional group in an alkene is the double bond.
c. Alcohol - Alcohols have a hydroxyl (-OH) group attached to a carbon atom. The functional group in an alcohol is the hydroxyl group.
d. Amine - Amines have a nitrogen atom attached to one or more carbon atoms. The functional group in an amine is the nitrogen atom.
The polarity of the atoms in the functional groups can vary. For example, oxygen in the hydroxyl group of alcohols is more electronegative than carbon, so it creates a polar bond.