Question

Which of the following compound(s) is/are aromatic?

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is B, D

To determine which of the given compounds are aromatic, we need to verify the following aromaticity criteria:

1. The molecule must be cyclic.
2. The molecule must be planar or flat, allowing for maximum overlap of the p-orbitals.
3. The molecule must have a complete delocalization of the π-electrons in the ring.
4. The molecule must follow Hückel's Rule, which states that the molecule must have (4n + 2) π-electrons, where n is a non-negative integer (0, 1, 2, 3, etc.).

Now, let's examine each option to identify which compounds are aromatic:

Compound 1: This compound is not aromatic because it does not satisfy all the aromaticity criteria. It might be cyclic and planar, but it doesn't meet the (4n + 2) π-electron rule for aromaticity.

Compound 2: This compound is aromatic. It is cyclic, planar, and has complete delocalization of π-electrons. Additionally, it satisfies Hückel's rule with (4n + 2) π-electrons, for example, with n = 1.

Compound 3: This compound is not aromatic. While it may be cyclic, it fails to meet the necessary criteria for π-electron delocalization or the (4n + 2) rule.

Compound 4: This compound is aromatic. It is cyclic, allows for π-electron delocalization, is planar, and also satisfies Hückel's rule, having (4n + 2) π-electrons with n=1 or another valid integer.

Conclusion: Based on the analysis, the aromatic compounds are:

Compound 2 and Compound 4.