Final answer:
Aromatic hydrocarbons contain a benzene ring or its derivative, while aliphatic hydrocarbons do not.
Step-by-step explanation:
An aromatic hydrocarbon is a type of organic compound that contains a benzene ring or a derivative of benzene. Aromatic compounds exhibit a special type of stability due to the delocalization of pi electrons in their ring structure. They are characterized by having a planar, cyclic, and conjugated system of p orbitals.
On the other hand, aliphatic hydrocarbons do not contain a benzene ring and are further classified as either alkanes, alkenes, or alkynes. Alkanes have only single bonds between carbon atoms, alkenes have at least one double bond, and alkynes have at least one triple bond.
Example of an aromatic hydrocarbon is benzene, while an example of an aliphatic hydrocarbon is propane.