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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3o2162

Which statements about Friedel-Crafts reactions of benzene are correct?

  1. Aalkylation with always gives only toluene, even when is in excess
  2. Balkylation with 1-chloropropane and gives mainly isopropylbenzene
  3. Cacylation stops at the monoacyl stage because the ketone product is deactivated
  4. Dacylation does not suffer from rearrangement of the electrophile

Answer: B, C, D

The propyl cation rearranges by a hydride shift to isopropyl. The acylium ion is resonance stabilised and does not rearrange. The acyl group deactivates the ring and prevents further acylation. Alkylation products are more reactive than benzene, so excess gives polyalkylation.
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