Polymers

Concept: Structure of natural rubber.

Step 1: Natural rubber = cis-1,4-polyisoprene.

Step 2: It is amorphous and has coiled structure.

Step 3: Syndiotactic arrangement is incorrect.
Conclusion:
Incorrect statement = (C)

Concept: Addition polymerisation of vinyl monomers.

Step 1: Monomer of PAN = CH =CH–CN (acrylonitrile).

Step 2: In addition polymerisation, double bond breaks and forms backbone.

Step 3: Polymer structure becomes [-CH –CH(CN)-] .

Step 4: CN group remains as side substituent on chain.
Conclusion:
Correct structure = option (B)