Zaymiey

🧪 Chemistry  ·  Polymers  ·  NEET & JEE

Step-growth polymerisation requires bifunctional monomers. High molecular weight is achieved only at:

Answer: Very high conversion (>99%) of functional groups.

  • A Very high conversion (>99%) of functional groups
  • B Low conversion of around 20% of the functional groups
  • C Moderate conversion near 50% of the functional groups present
  • D Any conversion level, since chain length is independent of conversion

Correct answer: A. Very high conversion (>99%) of functional groups

Explanation: Carothers equation shows Xn = 1/(1-p); only at p>0.99 do you get degree of polymerisation >100.

Addition vs Condensation PolymerisationAddition (e.g. polythene)n (CH₂=CH₂)-[-CH₂-CH₂-]ₙ-No atoms lost - monomers just join at the double bondCondensation (e.g. Nylon-6,6)HOOC-R-COOH + H₂N-R'-NH₂-[-CO-R-CO-NH-R'-NH-]ₙ-+ n H₂OA small molecule (water here) is eliminated at EVERY linking step

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.

Read the full Polymers notes →