Question

Find total number of aromatic compounds from the given organic molecules.

• A. 3
• B. 4
• C. 5
• D. 6

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
Identify aromatic compounds among the provided structures using Huckel's rule: cyclic, planar, fully conjugated system with $(4n+2)\pi$ electrons.
Step 2: Detailed Explanation:
(i) Cyclopropenyl cation: Cyclic, planar, conjugated, has $2\pi$ electrons ($4n+2, n=0$). Aromatic.
(ii) Quinone system: Not aromatic (non-conjugated cyclic system).
(iii) Benzoquinone: Not aromatic.
(iv) Anthracene/Phenanthrene derivative: Benzenoid system, has $14\pi$ electrons ($4n+2, n=3$). Aromatic.
(v) Tropylium cation: 7-membered ring, cyclic, planar, conjugated, has $6\pi$ electrons ($4n+2, n=1$). Aromatic.
(vi) Naphthalene: Benzenoid, has $10\pi$ electrons ($4n+2, n=2$). Aromatic.

Compounds (i), (iv), (v), and (vi) are aromatic. Total = 4.
Step 3: Final Answer:
The total number of aromatic compounds is 4.