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Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper II covers organic chemistry and spectroscopy.

Indian Forest Service (Mains), Chemistry optional · 2022 · Paper II

Q5(b). Stopping radical styrene polymerization

Question

Explain BPO-initiated styrene polymerization and the conversion of the active polymer into dead polymer by DPPH.

Answer in brief

Benzoyl peroxide generates radicals; growing polystyryl radicals are intercepted by the persistent DPPH radical.

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As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.

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Topic notes: polymers: polymerisation, Ziegler–Natta and molar mass, with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversfree-radical polymerizationbenzoyl peroxidepolystyreneDPPH inhibitorchain termination

All parts of Question 5