Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What best describes an aromatic hydrocarbon?

1. A hydrocarbon that is solid at room temperature

2. A compound that contains at least one carbon-carbon triple bond

3. A compound with a structure based on benzene: a ring of six carbon atoms

4. A hydrocarbon with a linear structure

The correct answer is: A compound with a structure based on benzene: a ring of six carbon atoms

An aromatic hydrocarbon is best described as a compound with a structure based on benzene, which consists of a ring of six carbon atoms. This unique structure is characterized by alternating double bonds and is often represented as a hexagonal ring. The stability and distinct properties of aromatic hydrocarbons arise from resonance, where electrons are delocalized across the ring structure. This results in a lower energy state and unique chemical behavior that differentiates aromatic hydrocarbons from aliphatic hydrocarbons, which do not have this ring structure. The properties of aromatic hydrocarbons lead to their widespread occurrence in various natural and synthetic compounds, such as toluene or naphthalene. Understanding the concept of resonance and the significance of the benzene ring is essential when studying aromatic compounds in organic chemistry, as these traits influence their reactivity, stability, and interactions with other substances.