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JEE Advanced levelSingle correct optionDifficulty 3 of 3o2147

Which sequence converts benzene mainly into 1-bromo-3-ethylbenzene?

  1. A(i) , ; (ii) ,
  2. B(i) , ; (ii) , ; (iii) , conc. HCl
  3. C(i) , ; (ii) , ; (iii) , conc. HCl
  4. D(i) , ; (ii) ,

Answer: B

A meta relationship between Br and an alkyl group needs a meta director on the ring while bromine is introduced. Acylation gives acetophenone, the acetyl group directs Br to the meta position, and Clemmensen reduction converts the acetyl group to ethyl. All other orders put Br and the side chain para (or ortho) to each other, since Br and ethyl are o/p directors.
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