The homopolymer formed from 4-hydroxybutanoic acid is :

Options

A. 1.`[ overset(O)overset(||)C (CH_(2))_(2) C-O]_(n)`
B. 2.`[ overset(O)overset(||)C (CH_(2))_(2) overset(O) overset(||)C-O]_(n)`
C. 3.`[O overset(O)overset(||)C (CH_(2))_(3) - O]_(n)`
D. 4.`[ overset(O)overset(||)C (CH_(2))_(3) - O]_(n)`

Explanation

To determine the homopolymer formed from 4-hydroxybutanoic acid, we can follow these steps:

### Step 1: Identify the structure of 4-hydroxybutanoic acid
4-hydroxybutanoic acid is a carboxylic acid with a hydroxyl group (-OH) attached to the fourth carbon of a four-carbon chain. Its structure can be represented as follows:

```
HO-CH2-CH2-CH(OH)-COOH
```

### Step 2: Determine the functional groups
In the structure of 4-hydroxybutanoic acid, we have:
- A carboxylic acid group (-COOH)
- A hydroxyl group (-OH)

### Step 3: Identify the polymerization process
When 4-hydroxybutanoic acid undergoes polymerization, the hydroxyl group can react with the carboxylic acid group to form ester linkages. This process is known as condensation polymerization, where water is eliminated during the formation of the polymer.

### Step 4: Draw the repeating unit of the polymer
The repeating unit of the polymer formed will be derived from the monomer (4-hydroxybutanoic acid). The polymer will consist of the ester linkages formed between the hydroxyl group and the carboxylic acid group. The structure of the repeating unit can be represented as follows:

```
-O-CH2-CH2-CH(OH)-CO-
```

### Step 5: Identify the name of the polymer
The polymer formed from 4-hydroxybutanoic acid is known as poly(4-hydroxybutanoate) or simply polybutyrolactone (PBL). This is because the polymerization leads to the formation of a cyclic ester (lactone) structure.

### Conclusion
The homopolymer formed from 4-hydroxybutanoic acid is poly(4-hydroxybutanoate).