Correct order of stability is:

Options

A. 1- butene `gt` Trans-2- butene `gt` Cis -2- butene
B. Trans-2-butene`gt`1-butene `gt` cis-2-butene
C. Trans-2-butene `gt` cis--2-butene `gt` 1-butene
D. Cis-2-butene `gt` Trans-2-butene`gt` 1 butene

Answer

To determine the correct order of stability among 1-butene, cis-2-butene, and trans-2-butene, we can analyze the structures and stability factors of these alkenes step by step.

### Step 1: Draw the Structures
1. **1-butene**: This is a straight-chain alkene with the double bond between the first and second carbon atoms. Its structure is:
```
CH2=CH-CH2-CH3
```

2. **cis-2-butene**: This alkene has the double bond between the second and third carbon atoms, with the two methyl groups (CH3) on the same side. Its structure is:
```
CH3
|
CH3-CH=CH-CH2
```

3. **trans-2-butene**: Similar to cis-2-butene, but the two methyl groups are on opposite sides of the double bond. Its structure is:
```
CH3
|
CH2=CH-CH3
```

### Step 2: Analyze Stability Factors
- **Hyperconjugation**: This is a stabilizing interaction that occurs when alkyl groups donate electron density through the σ-bonds to the adjacent π-bond. The more alkyl groups attached to the double bond, the more stable the alkene.

- **Steric Hindrance**: In alkenes, steric hindrance occurs when larger groups are adjacent to each other, which can destabilize the molecule. In general, trans alkenes are more stable than cis alkenes due to reduced steric hindrance.

### Step 3: Compare the Stability
1. **1-butene**: It has only two alpha hydrogens (hydrogens on the carbons adjacent to the double bond) and thus has limited hyperconjugation. This makes it the least stable alkene.

2. **cis-2-butene**: It has four alpha hydrogens, which allows for more hyperconjugation than 1-butene. However, due to steric hindrance from the adjacent methyl groups, it is less stable than trans-2-butene.

3. **trans-2-butene**: It has the same number of alpha hydrogens as cis-2-butene (four), but the methyl groups are on opposite sides of the double bond, reducing steric hindrance. This makes trans-2-butene the most stable alkene among the three.

### Conclusion
Based on the analysis:
- **Most Stable**: trans-2-butene
- **Moderately Stable**: cis-2-butene
- **Least Stable**: 1-butene

Thus, the correct order of stability is:
**trans-2-butene > cis-2-butene > 1-butene**

### Final Answer
The correct order of stability is: **trans-2-butene > cis-2-butene > 1-butene**.

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