From the compound shown below, choose which is/are aromatic.

Options

A.
B.
C.
D.

Explanation

To determine which of the given compounds are aromatic, we need to apply the criteria for aromaticity. A compound is considered aromatic if it meets the following conditions:

1. It must be cyclic.
2. It must be planar.
3. It must have a complete conjugated system (alternating single and double bonds).
4. It must contain \(4n + 2\) π electrons, where \(n\) is a non-negative integer.

Now, let's analyze each compound step by step.

### Step 1: Analyze Compound A
- **Count π Electrons**:
- The structure has 6 π electrons (2 from each double bond).
- **Check Conjugation**:
- The compound shows complete conjugation with alternating double and single bonds.
- **Planarity**:
- The compound is planar.
- **Aromaticity Check**:
- It satisfies the \(4n + 2\) rule (where \(n = 1\)).

**Conclusion**: Compound A is aromatic.

### Step 2: Analyze Compound B
- **Count π Electrons**:
- This compound has 10 π electrons.
- **Check Conjugation**:
- It shows conjugation with alternating double and single bonds.
- **Planarity**:
- However, due to hydrogen-hydrogen repulsion, one hydrogen atom is pushed out of the plane, disrupting planarity.
- **Aromaticity Check**:
- Although it has 10 π electrons, the loss of planarity means it cannot be aromatic.

**Conclusion**: Compound B is not aromatic.

### Step 3: Analyze Compound C
- **Count π Electrons**:
- This compound also has 10 π electrons.
- **Check Conjugation**:
- It shows complete conjugation with alternating double and single bonds.
- **Planarity**:
- The compound is planar.
- **Aromaticity Check**:
- It satisfies the \(4n + 2\) rule (where \(n = 2\)).

**Conclusion**: Compound C is aromatic.

### Step 4: Analyze Compound D
- **Count π Electrons**:
- This compound has 4 π electrons (2 from each double bond).
- **Check Conjugation**:
- It shows complete conjugation.
- **Planarity**:
- The compound is planar.
- **Aromaticity Check**:
- It does not satisfy the \(4n + 2\) rule (it has 4 π electrons which fits \(4n\), where \(n = 1\)), thus it is not aromatic.

**Conclusion**: Compound D is not aromatic.

### Final Summary:
- **Aromatic Compounds**: A and C
- **Non-Aromatic Compounds**: B and D