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MolSynapse / Question bank / Polymers / Geometry, tacticity and crosslinking in drawn chains
JEE Main levelSingle correct optionDifficulty 2 of 3pl259

A short fragment of a polymer chain (three repeat units, end groups shown) is drawn. How many of its C=C bonds have the two chain carbons on the same side (cis, Z)?

  1. A2
  2. B1
  3. C3
  4. D0

Answer: A

The fragment is a polyisoprene chain with mixed geometry. Assigning CIP descriptors with RDKit gives Z, E, Z. Counting the Z (cis) double bonds gives 2.
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