Which is maximum stable ?

Options

A. But-1-ene
B. cis-but-2-ene
C. trans-but-2-ene
D. All have equal

Answer

To determine which of the given hydrocarbons is the most stable, we will analyze the structures of but-1-ene, cis-but-2-ene, and trans-but-2-ene. Stability in alkenes is influenced by steric hindrance and the orientation of substituent groups around the double bond.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- We have three compounds to analyze: but-1-ene, cis-but-2-ene, and trans-but-2-ene.

2. **Draw the Structure of But-1-ene**:
- But-1-ene has the structure:
```
H2C=CH-CH2-CH3
```
- It has a double bond between the first and second carbon atoms.

3. **Draw the Structure of Cis-but-2-ene**:
- For cis-but-2-ene, the structure is:
```
CH3
|
H2C=C
|
CH3
```
- In this structure, both methyl (CH3) groups are on the same side of the double bond.

4. **Draw the Structure of Trans-but-2-ene**:
- The structure for trans-but-2-ene is:
```
CH3
|
H2C=C
|
H
```
- Here, the methyl group is on one side of the double bond, and a hydrogen atom is on the opposite side.

5. **Analyze Stability**:
- **But-1-ene**: This compound is relatively stable but does not have bulky groups that can cause steric hindrance.
- **Cis-but-2-ene**: The two bulky methyl groups are on the same side, leading to steric hindrance and repulsion between them, making it less stable.
- **Trans-but-2-ene**: The bulky groups are on opposite sides of the double bond, minimizing steric hindrance and repulsion. This orientation allows for greater stability.

6. **Conclusion**:
- Among the three compounds, **trans-but-2-ene** is the most stable due to the reduced steric hindrance between the bulky groups.

### Final Answer:
Trans-but-2-ene is the maximum stable compound.