What type of polymerization produces polyethene?

• A. Condensation polymerization
• B. Ionic polymerization
• C. Addition polymerization (free-radical addition)
• D. Step-growth polymerization

Answer: (C)

Ethene polymerizes by opening its carbon–carbon double bond and adding many monomer units to form a long chain without eliminating small molecules. This is addition polymerization, also described as free-radical addition in basic teaching, where the growing chain simply adds more ethene units to extend the polymer. Because no small molecule (like water or methanol) is released in the process, polyethylene is not formed by condensation or step-growth mechanisms, which involve by-products. Ionic polymerization is a different type of initiation that isn’t the typical route for making polyethylene in introductory contexts. So the correct description is addition polymerization (free-radical addition) for producing polyethene.