Which one of the following compounds will show geometrical isomerism ?

Options

A. A. 2-Butene
B. B. Propene
C. C. 1-Phenylpropene
D. D. 2-Methyl-2-butene

Answer

To determine which of the given compounds will show geometrical isomerism, we need to apply the criteria for geometrical isomerism in alkenes. Geometrical isomerism occurs when there is restricted rotation around a double bond, and it typically requires that the substituents attached to the double-bonded carbons are different.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to analyze each compound provided in the question to see if they can exhibit geometrical isomerism.

2. **Understanding Geometrical Isomerism**: For a compound to show geometrical isomerism, it must have:
- A double bond (C=C).
- Two different groups attached to each carbon of the double bond.
- The groups on each carbon must not be identical.

3. **Analyze Each Option**:
- **Option A: 2-Butene (CH3-CH=CH-CH3)**
- Structure: CH3-CH=CH-CH3
- Here, the groups attached to the first carbon (C1) are CH3 (methyl) and H (hydrogen), and the groups attached to the second carbon (C2) are CH3 and H.
- R1 (CH3) is not the same as R2 (H), and R3 (CH3) is not the same as R4 (H).
- **Conclusion**: 2-Butene can show geometrical isomerism.

- **Option B: Propene (CH3-CH=CH2)**
- Structure: CH3-CH=CH2
- Here, the groups attached to the first carbon (C1) are CH3 and H, while the second carbon (C2) has H and CH2.
- R1 (CH3) is not the same as R2 (H), but R3 (H) is the same as R4 (H).
- **Conclusion**: Propene cannot show geometrical isomerism.

- **Option C: 1-Phenylpropene (C6H5-CH=CH2)**
- Structure: C6H5-CH=CH2
- Here, the groups attached to the first carbon (C1) are C6H5 (phenyl) and H, while the second carbon (C2) has H and CH2.
- R1 (C6H5) is not the same as R2 (H), and R3 (H) is not the same as R4 (CH2).
- **Conclusion**: 1-Phenylpropene can show geometrical isomerism.

- **Option D: 2-Methyl-2-butene (CH3-C(CH3)=CH-CH3)**
- Structure: CH3-C(CH3)=CH-CH3
- Here, both groups attached to the second carbon (C2) are CH3.
- R1 (CH3) is not the same as R2 (H), but R3 (CH3) is the same as R4 (CH3).
- **Conclusion**: 2-Methyl-2-butene cannot show geometrical isomerism.

4. **Final Conclusion**: The compounds that can show geometrical isomerism are:
- **Option A: 2-Butene**
- **Option C: 1-Phenylpropene**

### Answer:
The compounds that will show geometrical isomerism are **A (2-Butene) and C (1-Phenylpropene)**.