Identify more stable canonical structure in each of the following pairs :
`overset(o+)CH_(2) - CH = CH - overset(Theta)O hArr CH_(2) = CH - CH = O `

Answer

To determine the more stable canonical structure between the two given structures, we will analyze each structure based on the principles of resonance and charge separation.

### Step 1: Identify the structures
We have two structures to analyze:
1. Structure 1: \( \overset{+}CH_2 - CH = CH - \overset{-}O \)
2. Structure 2: \( CH_2 = CH - CH = O \)

### Step 2: Analyze charge separation
- **Structure 1** contains a positive charge on the \( CH_2 \) group and a negative charge on the oxygen atom. This indicates charge separation, which generally leads to instability due to the presence of opposite charges.
- **Structure 2** does not have any charges. It is a neutral structure, which is typically more stable than charged structures.

### Step 3: Consider resonance
Both structures can be considered as resonance forms of each other. However, resonance structures that do not involve charge separation are more stable.
- In Structure 1, the presence of both a positive and a negative charge indicates charge separation, which can destabilize the molecule.
- Structure 2, being neutral and having a conjugated system (double bonds), allows for better delocalization of electrons, contributing to its stability.

### Step 4: Conclusion
Based on the analysis:
- **Structure 2** \( (CH_2 = CH - CH = O) \) is more stable than Structure 1 because it lacks charge separation and allows for better resonance stabilization.

### Final Answer
The more stable canonical structure is \( CH_2 = CH - CH = O \).

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