Acrolyn is a hard, horny and a high melting material. Which of the following represent its structure?

Options

A. `(CH_(2)-underset(COOC_(2)H_(5))underset(|)(CH)-)_(n)`
B. `(CH_(2)-underset(Cl)underset(|)(CH)-)_(n)`
C. `(CH_(2)-underset(CN)underset(|)(CH)-)_(n)`
D. `(-CH_(2)-overset(CH_(3))overset(|)underset(COOCH_(3))underset(|)C-)_(n)`

Explanation

To determine the correct structure of acrylonitrile (also known as polyacrylonitrile or orlon), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Acrylonitrile**:
- Acrylonitrile is a compound with the chemical formula CH2=CH-CN. It is a vinyl compound that contains a nitrile group (-CN) attached to a vinyl group (CH2=CH-).

2. **Formation of Polyacrylonitrile**:
- Acrylonitrile undergoes addition polymerization to form polyacrylonitrile (PAN). This means that multiple acrylonitrile monomers join together to form a long-chain polymer.

3. **Identifying the Structure**:
- The structure of polyacrylonitrile can be represented as a repeating unit derived from the acrylonitrile monomer. The repeating unit will have the structure:
- -[CH2-CH(CN)]-
- This indicates that each unit consists of a CH2 group and a CH group that is bonded to a CN group.

4. **Analyzing the Given Options**:
- The question provides multiple structural options for acrylonitrile. We need to identify which structure corresponds to the repeating unit of polyacrylonitrile.
- Look for the structure that includes the vinyl group (CH2=CH-) and the nitrile group (-CN) without any additional groups that would alter its identity (like COO or Cl).

5. **Eliminating Incorrect Options**:
- If any option contains groups such as COO (carboxyl) or Cl (chlorine), those can be eliminated as they do not represent acrylonitrile.
- After examining the options, the one that correctly represents the structure of polyacrylonitrile will be the correct answer.

6. **Conclusion**:
- After analyzing the options, the correct structure of acrylonitrile is identified as the one that has the repeating unit of -[CH2-CH(CN)]-.

### Final Answer:
- The correct option representing the structure of acrylonitrile is **option number 3**.