In propagation step, the reaction intermediate of radical polymerisation is

Options

A. Carbocation
B. Carbanion
C. Free radical
D. Carbene

Answer

To solve the question regarding the reaction intermediate of radical polymerization during the propagation step, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding Radical Polymerization**:
- Radical polymerization is a type of chain growth polymerization where monomers are added successively to form a polymer. This process involves the formation of radicals.

2. **Identifying the Steps in Radical Polymerization**:
- The radical polymerization process consists of four main steps:
1. **Initiation**: Formation of free radicals.
2. **Propagation**: Addition of monomers to the growing chain.
3. **Termination**: Combination of radicals to stop the reaction.
4. **Re-initiation** (optional in some cases).

3. **Focusing on the Propagation Step**:
- In the propagation step, the free radical generated in the initiation step reacts with a monomer (which typically has a double bond, such as C=C).
- This reaction leads to the formation of a new radical, which continues to react with more monomer units.

4. **Identifying the Reaction Intermediate**:
- During the propagation step, the reaction intermediate is a **free radical**.
- This is because the radical formed from the initiation step continues to react with other monomers, maintaining its radical character throughout the propagation.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the reaction intermediate of radical polymerization in the propagation step is a **free radical**.

### Final Answer:
The reaction intermediate of radical polymerization in the propagation step is a **free radical**.

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