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Saturday, 31 October

JEE Main 2023 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 10 April 2023, Shift 2, Chemistry Q78

Question 78 of 90 in this shift, Chemistry question 18 of 30, Section A.

Buna-S can be represented as:
  1. (1)−[CH2−CH=C(C6H5)−CH=CH−CH2]n−-[\mathrm{CH_2-CH=C(C_6H_5)-CH=CH-CH_2}]_n-
  2. (2)−[CH2−CH=CH−CH=C(C6H5)−CH2]n−-[\mathrm{CH_2-CH=CH-CH=C(C_6H_5)-CH_2}]_n-
  3. (3)−[CH=CH−CH=CH−CH(C6H5)−CH2]n−-[\mathrm{CH=CH-CH=CH-CH(C_6H_5)-CH_2}]_n-
  4. (4)−[CH2−CH=CH−CH2−CH(C6H5)−CH2]n−-[\mathrm{CH_2-CH=CH-CH_2-CH(C_6H_5)-CH_2}]_n-Official answer

Official answer

Option 4

NTA final key.

Chapter
Polymers
Topic
Polymers
Idea tested
Buna-S (SBR) Monomers

Same idea in other shifts

Asked 3× in all
  1. 24 Feb 2021, Shift 2 · Q48In polymer Buna-S : ‘S’ stands for :EasySingle correct
  2. 25 Feb 2021, Shift 1 · Q49Which statement is correct ?MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.