Answer: Addition of monomers to a growing reactive chain end.
- A Addition of monomers to a growing reactive chain end
- B Stepwise condensation of all monomers present in the mixture
- C Cross-linking of pre-existing linear polymer chains
- D Intramolecular cyclisation of the monomer before linking
Correct answer: A. Addition of monomers to a growing reactive chain end
Explanation: In chain-growth (addition) polymerisation, a reactive chain end (radical, cation, or anion) adds monomer units one at a time.
Addition polymerisation simply links monomers containing a double bond with nothing left over, while condensation polymerisation joins two different monomers through a reaction (often forming an ester or amide bond) that releases a small molecule like water at each step.
Concept context
Large molecules made of repeating monomer units. Covers addition and condensation polymerisation, natural and synthetic polymers (nylon, PVC, Bakelite, natural rubber), and their real-world industrial applications.