Answer: Combination or disproportionation of two radical chain ends.
- A Combination or disproportionation of two radical chain ends
- B Continued addition of monomer units to the growing chain
- C The initial homolysis reaction that generates the first radical
- D Chain transfer of the radical to a solvent molecule
Correct answer: A. Combination or disproportionation of two radical chain ends
Explanation: Two radical chain ends can combine (coupling) or disproportionate (H transfer) to terminate the chain.
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.