Which of these molecules does not exhibit resonance ?

Options

A. Ozone
B. Phenol
C. But -1,3-diene
D. ethanol

Answer

To determine which of the given molecules does not exhibit resonance, we will analyze each option step by step.

### Step 1: Analyze Ozone (O₃)
- Structure: O=O-O (with one oxygen having a negative charge and one oxygen having a positive charge).
- Ozone has a resonance structure because the double bond can shift between the two oxygen atoms.
- **Conclusion**: Ozone exhibits resonance.

### Step 2: Analyze Phenol (C₆H₅OH)
- Structure: The phenolic structure has a hydroxyl group (-OH) attached to a benzene ring.
- The lone pairs on the oxygen can delocalize into the benzene ring, allowing for multiple resonance structures.
- **Conclusion**: Phenol exhibits resonance.

### Step 3: Analyze 1,3-Butadiene (C₄H₆)
- Structure: CH₂=CH-CH=CH₂.
- The double bonds in 1,3-butadiene are conjugated, meaning they can share electrons and allow for resonance structures.
- **Conclusion**: 1,3-butadiene exhibits resonance.

### Step 4: Analyze Ethanol (C₂H₅OH)
- Structure: CH₃-CH₂-OH.
- In ethanol, there are no conjugated double bonds or lone pairs that can delocalize. The molecule consists of a simple alcohol structure without resonance.
- **Conclusion**: Ethanol does not exhibit resonance.

### Final Answer
- The molecule that does not exhibit resonance is **Ethanol (Option D)**.

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