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JEE Main levelOne or more correct optionsDifficulty 2 of 3nm015

Which of the following statements is/are correct?

  1. AThe degree of unsaturation of is 5.
  2. BA compound of formula can contain a ring.
  3. CBut-1-yne, buta-1,3-diene and cyclobutene are all , so each has a degree of unsaturation of 2.
  4. DThe degree of unsaturation of is 4.

Answer: C, D

But-1-yne, buta-1,3-diene and cyclobutene are C4H6 with DU = (8 + 2 - 6)/2 = 2, so the first statement is correct. C5H12 has DU = 0, so it has no ring or pi bond. C6H5Cl has DU = (12 + 2 - 5 - 1)/2 = 4, not 5, because a halogen counts like H. C7H9N has DU = (14 + 2 + 1 - 9)/2 = 4, so the last statement is correct.
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