Question

Polythene is the polymer obtained during polymerization of

• A. Propylene
• B. Acetylene
• C. Methylene
• D. Ethylene

Hint:

Polythene is formed from ethylene (CH$_2$=CH$_2$) by addition polymerization — look for the double bond in monomers when identifying polymer sources.

Answer 1

The Correct Option is D

Polythene, also known as polyethylene, is one of the most commonly used synthetic polymers.
It is formed by the addition polymerization of the monomer ethylene (CH$_2$=CH$_2$).
During polymerization, the double bond in ethylene breaks and allows the molecules to link together in a long repeating chain:
\[ n \, \text{CH}_2=\text{CH}_2 \longrightarrow [-\text{CH}_2-\text{CH}_2-]_n \]
This reaction is a classic example of addition polymerization, where no byproducts are formed and the entire monomer unit becomes part of the polymer chain.
Let’s analyze the incorrect options:
- Propylene (CH$_2$=CHCH$_3$): Polymerizes to form polypropylene, not polythene.
- Acetylene (C$_2$H$_2$): Can polymerize to form polyacetylene, not polythene.
- Methylene: This is not a stable monomer and doesn't exist freely for polymerization.
Thus, ethylene is the correct monomer for polythene.