Which of the following compounds display geomertical isomerism ?

Options

A. `H_(2)C = CHBr`
B. `H_(2)C = CBr_(2)`
C. `(Cl)HC=CH(Br)`
D. `Br_(2)C=C Cl_(2)`

Answer

To determine which of the given compounds display geometrical isomerism, we need to analyze each compound based on the criteria for geometrical isomerism, which typically occurs in alkenes with a carbon-carbon double bond (C=C) where the substituents on the double-bonded carbons are different.

### Step-by-Step Solution:

1. **Understanding Geometrical Isomerism**:
- Geometrical isomerism occurs when there are different groups attached to the carbon atoms involved in a double bond. For geometrical isomerism to exist, each carbon in the double bond must have two different substituents.

2. **Analyzing Each Compound**:
- **Option 1: CH2=CHBr**:
- Structure: H2C=CHBr
- Substituents on the first carbon (C1): H, H
- Substituents on the second carbon (C2): H, Br
- Since C1 has two identical substituents (H), this compound cannot exhibit geometrical isomerism.

- **Option 2: CH2=CBr2**:
- Structure: H2C=CBr2
- Substituents on C1: H, H
- Substituents on C2: Br, Br
- Again, C1 has two identical substituents (H), so this compound also cannot exhibit geometrical isomerism.

- **Option 3: ClCH=CHBr**:
- Structure: ClCH=CHBr
- Substituents on C1: Cl, H
- Substituents on C2: Br, H
- Both carbons have different substituents, allowing for geometrical isomerism. This compound can exist in two forms:
- **Cis** form: Cl and Br on the same side.
- **Trans** form: Cl and Br on opposite sides.

- **Option 4: Br2C=CCl2**:
- Structure: Br2C=CCl2
- Substituents on C1: Br, Br
- Substituents on C2: Cl, Cl
- Since both carbons have identical substituents, this compound cannot exhibit geometrical isomerism.

3. **Conclusion**:
- Out of the four options, only **Option 3 (ClCH=CHBr)** can show geometrical isomerism.

### Final Answer:
Only the compound **ClCH=CHBr** displays geometrical isomerism.