Which of the following belongs to the class of vinyl halides ?

Options

A. `CH_(2) =CH -CHBr -CH_(3)`
B. `CH_(3) -underset(Br) underset(|)(C ) = CH_(2)`
C. `HC -= C - Br`
D. `CH_(3) -CH = CH - CH_(2)- Br`

Answer

To determine which of the given options belongs to the class of vinyl halides, we first need to understand the definition and structure of vinyl halides.

### Step-by-Step Solution:

1. **Understanding Vinyl Halides**:
- Vinyl halides are compounds where a halogen atom (like Cl, Br, I, etc.) is directly attached to a carbon atom that is part of a carbon-carbon double bond (C=C).
- The general structure of a vinyl halide can be represented as R-CH=CH-X, where R is any alkyl group and X is the halogen.

2. **Identifying the Structure**:
- To identify whether a compound is a vinyl halide, we need to look for the presence of a carbon-carbon double bond and check if a halogen is attached to one of the carbons involved in that double bond.

3. **Analyzing the Options**:
- We will examine each option provided in the question to see if it fits the criteria for a vinyl halide.

4. **Option Analysis**:
- **Option A**: If this option shows a halogen attached to a carbon that is not part of a double bond, it is not a vinyl halide.
- **Option B**: If this option shows a halogen attached to one of the carbons in a double bond (C=C), then it is a vinyl halide.
- **Option C**: If this option shows a triple bond or a halogen attached to a carbon that is not part of a double bond, it is not a vinyl halide.
- **Option D**: Similar to option A, if it shows a halogen attached to a carbon that is not part of a double bond, it is not a vinyl halide.

5. **Conclusion**:
- After analyzing all options, the correct option that shows a halogen attached to a carbon in a double bond is **Option B**. This confirms that it belongs to the class of vinyl halides.

### Final Answer:
**Option B** is the correct answer as it belongs to the class of vinyl halides.