when vinyl and allyl are joined each other, we get:

Options

A. Conjugated alkadiene
B. Cumulative alkadiene
C. Isolated alkadiene
D. Allenes

Answer

To solve the question of what we get when vinyl and allyl are joined together, we can follow these steps:

### Step-by-Step Solution:

1. **Define Vinyl and Allyl Groups**:
- The **vinyl group** is represented as \( R-CH=CH_2 \), where \( R \) is any alkyl group.
- The **allyl group** is represented as \( R-CH_2-CH=CH_2 \).

2. **Combine the Two Groups**:
- When we combine the vinyl group and the allyl group, we need to consider how they can be connected.
- The vinyl group can be attached to the allyl group at the terminal carbon of the allyl group.

3. **Construct the Structure**:
- If we attach the vinyl group to the allyl group, we can visualize it as:
\[ R-CH=CH_2 + R'-CH_2-CH=CH_2 \rightarrow R-CH=CH-CH_2-CH=CH_2 \]
- Here, \( R \) and \( R' \) can be the same or different alkyl groups.

4. **Identify the Type of Diene Formed**:
- The resulting compound has two double bonds that are not adjacent to each other, which means they are separated by a single bond.
- This configuration leads to a structure known as an **isolated diene**.

5. **Conclusion**:
- Therefore, when vinyl and allyl groups are joined together, the product is an **isolated diene**.

### Final Answer:
When vinyl and allyl are joined together, we get an **isolated diene**.

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