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JEE Main levelSingle correct optionDifficulty 2 of 3g3179

At low temperature, electrophilic substitution of naphthalene occurs faster at C-1 than at C-2. The best explanation is that

  1. Athe arenium ion from C-1 attack has more resonance structures, two of which keep an intact benzene ring, whereas the C-2 ion has only one such structure
  2. Bthe arenium ion from C-1 attack is a tertiary carbocation
  3. Cthe arenium ion from C-2 attack has more resonance structures that keep an intact benzene ring
  4. Dthe C-2 position is more hindered than C-1 by the peri hydrogen

Answer: A

Attack at C-1 gives an ion with four resonance forms, two of which keep an aromatic benzene ring. Attack at C-2 gives three forms, only one of which keeps it. The more delocalised ion lies lower in energy, so its transition state is lower and C-1 attack is faster.
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