Which one of the following molecules can serve as a monomer for an addition polymer?

Options

A. `H_2C=CH-C_6H_5`
B. `H_2C=CHCN`
C. `ClCH=CH_2`
D. All of these

Answer

To determine which of the given molecules can serve as a monomer for an addition polymer, we need to identify if they contain a double bond (or multiple bonds) that can participate in the polymerization process. Here’s how to analyze the options step by step:

### Step-by-Step Solution:

1. **Understanding Addition Polymers**:
- Addition polymers are formed by the repeated addition of monomer units that contain double bonds (C=C) or triple bonds (C≡C). The double or triple bond must be able to break to allow for the formation of new single bonds with other monomers.

2. **Analyzing the Given Molecules**:
- We need to check each molecule to see if it has a double bond that can be broken to form a polymer.

3. **Option 1: CH2=CHC6H5**:
- This molecule has a double bond between the first two carbon atoms (C=C).
- When the double bond breaks, it can connect with another monomer, allowing it to serve as a monomer for an addition polymer.

4. **Option 2: CH2=CHCN**:
- This molecule also has a double bond (C=C) between the first two carbon atoms.
- Similar to the first option, the double bond can break and allow for polymerization.

5. **Option 3: CH2=CHCl**:
- This molecule also contains a double bond (C=C).
- The double bond can break, allowing it to participate in the formation of an addition polymer.

6. **Conclusion**:
- All three molecules (CH2=CHC6H5, CH2=CHCN, and CH2=CHCl) contain double bonds and can serve as monomers for addition polymers. Therefore, the correct answer is that all three can act as monomers.

7. **Final Answer**:
- The correct choice is **Option 4: All of these**.