Which of the following has the miximum number of resonating structure ?

Options

A. Benzene
B. Naphthalene
C. Anthracene
D. Phenanthrene

Explanation

To determine which of the given compounds has the maximum number of resonating structures, we will analyze each compound: benzene, naphthalene, anthracene, and phenanthrene.

### Step-by-Step Solution:

1. **Benzene (C6H6)**:
- Benzene has a cyclic structure with alternating double bonds.
- The two resonating structures can be represented as:
- Structure 1: C1=C2-C3=C4-C5=C6
- Structure 2: C1-C2=C3-C4=C5-C6
- **Total Resonating Structures**: 2

2. **Naphthalene (C10H8)**:
- Naphthalene consists of two fused benzene rings.
- The resonating structures can be represented as:
- Structure 1: C1=C2-C3=C4-C5=C6-C7=C8
- Structure 2: C1-C2=C3-C4=C5-C6=C7=C8
- Structure 3: C1=C2-C3=C4-C5=C6-C7=C8 (with the double bonds shifted)
- **Total Resonating Structures**: 3

3. **Anthracene (C14H10)**:
- Anthracene consists of three linearly arranged fused benzene rings.
- The resonating structures can be represented as:
- Structure 1: C1=C2-C3=C4-C5=C6-C7=C8-C9=C10
- Structure 2: C1-C2=C3-C4=C5-C6=C7-C8=C9-C10
- Structure 3: C1=C2-C3=C4-C5=C6-C7=C8-C9=C10 (with the double bonds shifted)
- Structure 4: C1-C2=C3-C4=C5-C6-C7=C8-C9=C10 (another shifting)
- **Total Resonating Structures**: 4

4. **Phenanthrene (C14H10)**:
- Phenanthrene consists of three fused benzene rings in a different arrangement than anthracene.
- The resonating structures can be represented as:
- Structure 1: C1=C2-C3=C4-C5=C6-C7=C8-C9=C10
- Structure 2: C1-C2=C3-C4=C5-C6=C7-C8=C9-C10
- Structure 3: C1=C2-C3=C4-C5=C6-C7=C8-C9=C10 (with the double bonds shifted)
- Structure 4: C1-C2=C3-C4=C5-C6-C7=C8-C9=C10 (another shifting)
- Structure 5: C1=C2-C3=C4-C5=C6-C7=C8-C9=C10 (another arrangement)
- **Total Resonating Structures**: 5

### Conclusion:
After analyzing all four compounds, we find that **phenanthrene** has the maximum number of resonating structures, which is **5**. Therefore, the correct answer is **option D: phenanthrene**.