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GATE 2025 Chemical Engineering, Q27 · Chemical Technology

The correct answer is A, Chlorination followed by Dehydrochlorination.

Question

In the production of polyvinyl chloride (PVC) from ethylene and chlorine, the sequential order of reactions is

  • A. Chlorination followed by Dehydrochlorination
  • B. Dehydrochlorination followed by Chlorination
  • C. Hydrogenation followed by Chlorination
  • D. Dehydrochlorination followed by Hydrogenation

Official answer: Chlorination followed by Dehydrochlorination

Why

GATE 2025 official key: (A). Ethylene is first chlorinated to 1,2-dichloroethane (EDC), which is then cracked via dehydrochlorination (pyrolysis) to yield vinyl chloride monomer.

Explanation cross-checked for consistency. Final answer matches the official IIT answer key.

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