The monomer unit of polythene is

Options

A. `CF_2 = CF_2`
B. `CH_2 = CH_2`
C. `CH_2 = CHCl`
D. `CH_2 = CHCN`

Explanation

To determine the monomer unit of polythene, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Polythene**:
Polythene, also known as polyethylene, is a type of polymer commonly used in various applications.

2. **Understand Monomers**:
A monomer is a small molecule that can join together with other similar molecules to form a polymer.

3. **Identify the Monomer of Polythene**:
The monomer unit of polythene is ethene, which has the chemical formula \( \text{C}_2\text{H}_4 \) or can be represented as \( \text{CH}_2=\text{CH}_2 \).

4. **Polymerization Process**:
Polythene is formed through the polymerization of ethene. This process typically occurs under specific conditions of temperature (around 350 to 570 Kelvin) and pressure (between 1000 to 1500 atm).

5. **Conclusion**:
Therefore, the monomer unit of polythene is ethene.

### Final Answer:
The monomer unit of polythene is ethene (\( \text{CH}_2=\text{CH}_2 \)).

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