Polyvinyl alcohol is an important polymer. The structure is given below
`(-CH_(2)-underset(OH)underset("| ")"CH"-CH_(2)-underset(OH)underset("| ")"CH"-CH_(2)-underset(OH)underset("| ")"CH"-)`
It is prepared by polymerization of

Options

A. `CH_(2)=CH-OH`
B. `CH_(2)=CH-OCOCH_(3)`, followed by hydrolysis
C. `CH_(2)=CH-CN`, followed by hydrolysis
D. `CH_(2)=CH-COOCH_(3)`, followed by hydrolysis

Answer

To determine what polyvinyl alcohol is prepared from, we need to understand the process of polymerization and the specific monomer involved in the formation of polyvinyl alcohol.

### Step-by-Step Solution:

1. **Understanding Polymers and Monomers**:
- Polymers are large molecules made up of repeating structural units called monomers.
- The process of combining monomers to form a polymer is known as polymerization.

2. **Identifying Polyvinyl Alcohol**:
- Polyvinyl alcohol (PVA) is a synthetic polymer that is soluble in water and is known for its film-forming properties.
- The structure of polyvinyl alcohol consists of repeating units of -CH2-CHOH-.

3. **Identifying the Monomer**:
- Polyvinyl alcohol is specifically derived from polyvinyl acetate (PVAc).
- The chemical structure of polyvinyl acetate is CH2=CHOCOCH3.

4. **Polymerization Process**:
- Polyvinyl acetate undergoes hydrolysis (reaction with water) to convert into polyvinyl alcohol.
- The hydrolysis of polyvinyl acetate involves breaking the ester bond and replacing it with a hydroxyl group (-OH), resulting in the formation of polyvinyl alcohol.

5. **Conclusion**:
- Therefore, polyvinyl alcohol is prepared by the hydrolysis of polyvinyl acetate.

### Final Answer:
Polyvinyl alcohol is prepared by the hydrolysis of polyvinyl acetate.

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