Which of the following is aromatic in nature ?

Options

A.
B.
C.
D. All of these

Answer

To determine which of the given compounds is aromatic in nature, we can follow these steps:

### Step 1: Understand Aromaticity
Aromatic compounds are defined by their ability to follow Huckel's rule, which states that a compound is aromatic if it has a planar cyclic structure with a continuous overlap of p-orbitals and contains \(4n + 2\) π (pi) electrons, where \(n\) is a non-negative integer (0, 1, 2, ...).

### Step 2: Identify the Number of π Electrons
For each compound, we need to count the number of π electrons present in the structure. This includes electrons from double bonds and lone pairs that can participate in delocalization.

### Step 3: Check Each Compound
1. **First Compound**:
- Count π electrons: It has 2 π electrons from the double bond.
- Check if it fits Huckel's rule: \(n = 0\) gives \(4(0) + 2 = 2\). This compound is aromatic.

2. **Second Compound**:
- Count π electrons: It has 2 π electrons from the double bond and 2 from a lone pair, totaling 4 π electrons.
- Check if it fits Huckel's rule: \(n = 1\) gives \(4(1) + 2 = 6\). This compound is aromatic.

3. **Third Compound**:
- Count π electrons: It has 2 π electrons from the double bond and 2 from another double bond, totaling 4 π electrons, plus 2 from a lone pair, totaling 6 π electrons.
- Check if it fits Huckel's rule: \(n = 1\) gives \(4(1) + 2 = 6\). This compound is aromatic.

### Step 4: Conclusion
Since all the compounds have been shown to have π electron counts that fit Huckel's rule, we conclude that all of them are aromatic in nature.

### Final Answer:
**All of the given compounds are aromatic in nature.**