Which of the following compounds will exhibit geometrical isomerism?

Options

A. 3 - Phenyl - 1 - butene
B. 2 - Phenyl - 1 - butene
C. 1, 1 - Diphenyl - 1- propane
D. 1 - Phenyl - 2 - butene

Answer

To determine which of the given compounds will exhibit geometrical isomerism, we need to analyze the structure of each compound based on the presence of a double bond and the arrangement of substituents around that bond.

### Step-by-Step Solution:

1. **Understanding Geometrical Isomerism**:
- Geometrical isomerism (also known as cis-trans isomerism) occurs in compounds with restricted rotation around a double bond (typically alkenes). For geometrical isomerism to be possible, each carbon of the double bond must have two different substituents.

2. **Analyzing Each Compound**:
- **Option 1: 3-Phenyl-1-butene**
- Structure: The double bond is between the first and second carbon. The first carbon has a phenyl group and two hydrogen atoms, while the second carbon has two hydrogen atoms.
- Conclusion: This compound cannot exhibit geometrical isomerism because one of the doubly bonded carbons has identical substituents (two hydrogens).

- **Option 2: 2-Phenyl-1-butene**
- Structure: The double bond is between the first and second carbon. The first carbon has a phenyl group and one hydrogen, while the second carbon has two hydrogens.
- Conclusion: This compound also cannot exhibit geometrical isomerism for the same reason as the first option; one of the doubly bonded carbons has identical substituents.

- **Option 3: Propane with two phenyl groups**
- Structure: The first carbon has two phenyl groups and the second carbon has one hydrogen and the third carbon has two hydrogens.
- Conclusion: This compound cannot exhibit geometrical isomerism because the first carbon has identical substituents (two phenyl groups).

- **Option 4: 2-Butene**
- Structure: The double bond is between the first and second carbon. The first carbon has a phenyl group and two hydrogens, while the second carbon has two hydrogens.
- Conclusion: This compound can exhibit geometrical isomerism because each of the doubly bonded carbons has different substituents (one has a phenyl group and the other has two hydrogens).

3. **Final Answer**:
- The compound that exhibits geometrical isomerism is **Option 4: 2-Butene**.