Which of the following is vinylic bromide ?

Options

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

Explanation

To determine which of the given compounds is a vinylic bromide, we need to understand the definitions of allylic and vinylic positions in relation to a double bond in an alkene.

### Step-by-Step Solution:

1. **Identify the Structure of the Compounds**:
- We need to examine the structures of the compounds provided in the question. Each compound will have a double bond (alkene) and a bromine substituent.

2. **Understand Allylic and Vinylic Positions**:
- **Allylic Position**: The carbon atom adjacent to the carbon of the double bond. If a bromine atom is attached to this carbon, it is termed an allylic bromide.
- **Vinylic Position**: The carbon atom that is part of the double bond itself. If a bromine atom is attached to this carbon, it is termed a vinylic bromide.

3. **Analyze Each Compound**:
- For each compound, identify where the bromine is attached in relation to the double bond.
- If bromine is attached to the carbon that is part of the double bond, it is a vinylic bromide.
- If bromine is attached to the carbon next to the double bond, it is an allylic bromide.

4. **Determine the Correct Answer**:
- After analyzing each compound:
- If Compound A has bromine on an allylic carbon, it is an allylic bromide.
- If Compound B has bromine on a vinylic carbon, it is a vinylic bromide.
- If Compound C has bromine on an allylic carbon, it is again an allylic bromide.
- The correct answer is the compound where bromine is attached to the vinylic carbon.

### Conclusion:
The compound identified as having bromine attached to a vinylic carbon is the correct answer. Based on the analysis, the answer is **Compound B**.