JEE Main 2023 · 11 April · evening · Single correct · +4 / −1
Given below are two statements :
Statement I : Ethene at 333 to 343 K and 6-7 atm pressure in the presence of AlEt₃ and TiCl₄ undergoes addition polymerization to give LDP.
Statement II : Caprolactam at 533-543 K in H₂ O through step growth polymerizes to give Nylon 6.
In the light of the above statements, choose the correct answer from the options given below:
- (a) Both Statement I and Statement II are true
- (b) Statement I is true but Statement II is false
- (c) Statement I is false but Statement II is true
- (d) Both Statement I and Statement II are false
Answer and solution
Answer (c) Statement I is false but Statement II is true
Solution
Chemistry ma’am · 3 steps
Ziegler–Natta catalyst with ethene gives straight chains, so the product is HDPE, not LDP.
- Statement I. AlEt₃ with TiCl₄ is the Ziegler–Natta catalyst. At 333 to 343 K and 6 to 7 atm it adds ethene units into straight, unbranched chains that pack closely. That polymer is high density polythene (HDP), so Statement I is false.
Polythene Conditions Chain shape LDP 350 to 570 K, 1000 to 2000 atm, traces of O₂ or a peroxide (free radical) highly branched HDP 333 to 343 K, 6 to 7 atm, AlEt₃ + TiCl₄ (Ziegler–Natta) linear - Statement II. Caprolactam heated with water at 533 to 543 K opens its ring and joins up through amide links, one step at a time. This is step growth (condensation) polymerisation, and the product is Nylon 6. Statement II is true.
- So. Statement I is false and Statement II is true, which is option (c).
The idea to keep. For polythene, match the conditions. High pressure with a free radical initiator gives branched LDP. Low pressure with the Ziegler–Natta catalyst gives linear HDP.
Answer from the NTA final answer key. Solution by PrepWiser.