The chemical system that is non`-` aromatic is

Options

A.
B.
C.
D.

Answer

To determine which chemical system is non-aromatic, we need to follow a few steps based on the characteristics of aromatic compounds. Here’s a step-by-step solution:

### Step 1: Understand the Criteria for Aromaticity
A compound is considered aromatic if it meets the following criteria:
1. It must be cyclic.
2. It must have complete conjugation (p-orbitals overlapping).
3. It must follow Huckel's rule, which states that the compound must have (4n + 2) π electrons, where n is a non-negative integer.

### Step 2: Analyze the Given Options
Assuming we have three options to analyze, we need to check each one against the criteria for aromaticity.

- **Option 1:** Check if it is cyclic, has complete conjugation, and follows Huckel's rule.
- **Option 2:** Again, check for cyclic structure, complete conjugation, and Huckel's rule.
- **Option 3:** Check for cyclic structure, conjugation, and whether it follows Huckel's rule.

### Step 3: Identify Non-Aromatic Characteristics
For a compound to be non-aromatic, it must:
1. Not be cyclic, or
2. Lack complete conjugation, or
3. Not follow Huckel's rule.

### Step 4: Evaluate Each Option
- **Option 1:** If it is cyclic, has complete conjugation, and follows Huckel's rule, it is aromatic.
- **Option 2:** If it is cyclic, has complete conjugation, and follows Huckel's rule, it is aromatic.
- **Option 3:** If it is cyclic but lacks complete conjugation (for example, due to the presence of a positive charge disrupting the π system), then it does not meet the criteria for aromaticity and is classified as non-aromatic.

### Conclusion
Based on the analysis, the third option is identified as non-aromatic due to the lack of complete conjugation.

### Final Answer
The chemical system that is non-aromatic is **Option 3**.

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