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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ap232

The diol shown is treated with cold dilute acid. Choose all correct statements.

  1. AThe first carbocation forms at the carbon carrying the two phenyl groups.
  2. BA phenyl group migrates to give a benzoyl compound as the major product.
  3. CThe major product contains a quaternary carbon bearing a methyl group and two phenyl groups.
  4. DThe major product gives a positive iodoform test.

Answer: A, C, D

The diol is 2-methyl-1,1-diphenylpropane-1,2-diol. The diphenylcarbinyl cation is the stabler one, so water leaves there (A) and a methyl group migrates, not a phenyl (B is wrong). The product, 3,3-diphenylbutan-2-one, has as a quaternary carbon (C) and a group, so it gives iodoform (D).
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