Which of the following anions is resonance destabilized?

Options

A.
B.
C.
D.

Answer

To determine which of the given anions is resonance destabilized, we need to analyze the resonance structures of each anion and how they affect stability. Here’s a step-by-step solution:

### Step 1: Identify the Anions
We need to look at the four anions provided in the question. Let’s denote them as A, B, C, and D for analysis.

### Step 2: Analyze Each Anion for Resonance
- **Anion A**: Draw the resonance structures. If the negative charge can be delocalized through resonance, it will increase stability.
- **Anion B**: Similar to Anion A, draw the resonance structures and check if the negative charge can be delocalized. If it can, this will also indicate stability.
- **Anion C**: This anion is part of a benzene ring. The electrons are already delocalized in the aromatic system. If the anion disturbs this aromaticity, it will lead to destabilization.
- **Anion D**: Analyze the resonance structures. If it can maintain aromaticity or has effective delocalization, it will be stable.

### Step 3: Evaluate Stability
- **Anion A**: If resonance structures show effective delocalization, it is resonance stabilized.
- **Anion B**: If resonance structures show effective delocalization, it is also resonance stabilized.
- **Anion C**: If the resonance structures show that introducing the anion disrupts the aromatic system, it will be resonance destabilized.
- **Anion D**: If resonance structures maintain aromaticity, it will be resonance stabilized.

### Step 4: Conclusion
After analyzing all four anions, we find that **Anion C** is resonance destabilized due to the disruption of aromaticity when the anion participates in resonance. This leads to a decrease in stability.

### Final Answer
The anion that is resonance destabilized is **C**.

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