Answer: Styrene (vinylbenzene).
- A Styrene (vinylbenzene)
- B Ethylene under usual circumstances
- C Propylene according to most researchers
- D Acrylonitrile in the majority of cases studied
Correct answer: A. Styrene (vinylbenzene)
Explanation: Polystyrene is made by addition polymerisation of styrene (C6H5-CH=CH<sub>2</sub>).
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.