Question

Which of the following is non-aromatic?

• A. cyclohexene
• B. benzene
• C. naphthalene
• D.

Hint:

When identifying aromatic compounds, remember to check if the compound has a conjugated system of pi electrons and follows Hückel's rule. Non-aromatic compounds do not satisfy these criteria.

Answer 1

The Correct Option is A

Aromatic compounds are those that are cyclic, planar, and have a conjugated system of electrons (alternating single and double bonds) that satisfies Hückel's rule, which means the number of pi electrons in the conjugated system should be \(4n + 2\) (where \(n\) is a non-negative integer). - Benzene is aromatic because it has six pi electrons, satisfying Hückel’s rule (\(n = 1\)). - Naphthalene is aromatic because it also has a conjugated system of pi electrons and satisfies Hückel’s rule. - Cyclohexene, however, does not have a conjugated system of pi electrons as it contains a single double bond. Therefore, it is non-aromatic. Cyclohexene does not satisfy the conditions required for aromaticity. Thus, the correct answer is cyclohexene.