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A hydrocarbon 'Y' with the molecular formula C ₈ H ₁₂ absorbs two moles of H ₂ on catalytic hydrogenation. On reductive ozonolysis, one mole of 'Y' yields one mole of hexane- 2,5 -dione and one mole of ethanedial. The hydrocarbon 'Y' is :

Options

  1. A1,4 -dimethylcyclohexa- 1,4 -diene
  2. B1,4 -dimethylcyclohexa- 1,3 -diene
  3. C2,3 -dimethylcyclohexa- 1,3 -diene
  4. D1,2 -dimethylcyclohexa- 1,4 -diene

Correct answer

B. 1,4 -dimethylcyclohexa- 1,3 -diene

Step-by-step solution

Degree of unsaturation (DBE) for C ₈ H ₁₂ = 8 + 1 - 12 2 = 3 . Since one mole of 'Y' absorbs two moles of H ₂ , it contains two double bonds. The remaining 1 DBE indicates the presence of one ring. Reductive ozonolysis of 'Y' yields hexane- 2,5 -dione ( CH ₃ COCH ₂ CH ₂ COCH ₃ ) and ethanedial ( OHC - CHO ). To find the structure of 'Y', we perform a retrosynthetic analysis by removing the oxygen atoms from the carbonyl groups of the products and connecting the respective carbon atoms with double bonds. Aligning th

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