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 compounds belongs to the class of vinyl halides, we need to understand the structural characteristics that define vinyl halides and how they differ from allyl halides.

### Step-by-Step Solution:

1. **Understanding Vinyl Halides**:
- Vinyl halides are defined as compounds where a halogen atom (X) is directly bonded to a carbon atom that is part of a carbon-carbon double bond (C=C).
- The general structure can be represented as R-CH=CH-X, where X is a halogen (like Br, Cl, etc.).

2. **Understanding Allyl Halides**:
- Allyl halides, on the other hand, have the halogen attached to a carbon atom that is adjacent to the carbon-carbon double bond, not directly to it.
- The general structure can be represented as R-CH2-CH=CH-X.

3. **Analyzing the Options**:
- **Option 1**: C=C-CH2-Br: In this structure, the bromine (Br) is attached to a carbon that is not part of the double bond (it is attached to CH2). Thus, this is an allyl halide.
- **Option 2**: C=C(Br)-C: Here, the bromine is directly attached to the carbon that is part of the double bond. Therefore, this compound is a vinyl halide.
- **Option 3**: C≡C-Br: This structure contains a triple bond, which does not fit the definition of vinyl halides. Hence, it does not belong to this class.
- **Option 4**: C=C-CH2-Cl: Similar to option 1, the chlorine (Cl) is attached to a carbon adjacent to the double bond, making this an allyl halide.

4. **Conclusion**:
- After analyzing all the options, we find that **Option 2** is the only compound that fits the definition of a vinyl halide.

### Final Answer:
The compound that belongs to the class of vinyl halides is **Option 2**.