The monomer of the polymer `[-CH_(2)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(2)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH_(2)-]_(n)`

Options

A. `H_(2)C = C(CH_(3))_(2)`
B. `(CH_(3))_(2)C= C(CH_(3))_(2)`
C. `CH_(3)CH = CH.CH_(3)`
D. `CH_(3).CH = CH_(2)`

Answer

To determine the monomer of the given polymer, we can follow these steps:

### Step 1: Analyze the Polymer Structure
The polymer is represented as:
`[-CH₂-CH(CH₃)-CH(CH₃)-CH₂-]ₙ`
This indicates a repeating unit in the polymer chain.

### Step 2: Identify the Repeating Unit
From the structure, we can see that the repeating unit consists of:
- Two carbon atoms (CH₂) at the ends.
- Two carbon atoms (CH(CH₃)) in the middle, each having a methyl (CH₃) group attached.

### Step 3: Look for Double Bonds
Polymers are often formed from monomers that contain double bonds. In this case, we can infer that the monomer must have a double bond that allows it to polymerize into the given structure.

### Step 4: Construct the Monomer
To find the monomer, we can visualize the structure by introducing a double bond. The double bond can be placed between two carbon atoms in the middle of the structure. Therefore, we can represent the monomer as:
- CH₂=CH(CH₃)-CH(CH₃)

### Step 5: Confirm the Monomer
Now, we can confirm that the monomer we derived can indeed polymerize to form the original polymer structure. The double bond in the monomer allows for the addition of more monomer units, resulting in the polymer chain.

### Conclusion
The monomer of the polymer `[-CH₂-CH(CH₃)-CH(CH₃)-CH₂-]ₙ` is:
**CH₂=CH(CH₃)-CH(CH₃)**