The alkene that exhibits geometrical isomerism is

Options

A. propene
B. 2-methylpropene
C. 2-butene
D. 2-methyl-2-butene

Explanation

To determine which alkene exhibits geometrical isomerism, we need to analyze the given options based on the criteria for geometrical isomerism (also known as cis-trans isomerism). This occurs when there is restricted rotation around a double bond and when two different groups are attached to each carbon of the double bond.

### Step-by-Step Solution:

1. **Understand the Criteria for Geometrical Isomerism**:
- For an alkene to exhibit geometrical isomerism, it must have:
- A double bond (C=C).
- Different groups attached to each carbon of the double bond (i.e., A ≠ B and C ≠ D).

2. **Analyze Each Option**:
- **Option A: Propene (CH3-CH=CH2)**:
- The structure is CH3-CH=CH2.
- The double bond is between the second and third carbon.
- Both carbons involved in the double bond have identical hydrogen atoms (H), making it impossible to have different groups.
- **Conclusion**: Propene does not exhibit geometrical isomerism.

- **Option B: 2-Methylpropene (CH3-CH(CH3)-CH2)**:
- The structure is CH3-CH(CH3)-CH2.
- The double bond is between the second and third carbon.
- Again, there are identical groups (H) on the double-bonded carbons.
- **Conclusion**: 2-Methylpropene does not exhibit geometrical isomerism.

- **Option C: 2-Butene (CH3-CH=CH-CH3)**:
- The structure is CH3-CH=CH-CH3.
- The double bond is between the second and third carbon.
- The groups attached to the double-bonded carbons are different (one has CH3 and the other has H).
- **Conclusion**: 2-Butene can exhibit geometrical isomerism (cis and trans forms).

- **Option D: 2-Methyl-2-butene (CH3-C(CH3)=CH-CH3)**:
- The structure is CH3-C(CH3)=CH-CH3.
- The double bond is between the second and third carbon.
- Both groups on the double-bonded carbon are identical (CH3), which means it cannot exhibit geometrical isomerism.
- **Conclusion**: 2-Methyl-2-butene does not exhibit geometrical isomerism.

3. **Final Answer**:
- The alkene that exhibits geometrical isomerism is **Option C: 2-Butene**.