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JEE Main levelSingle correct optionDifficulty 2 of 3o1024

The solvolysis of is carried out in pure ethanol and then in 50% aqueous ethanol. The rate in the aqueous mixture is

  1. Asmaller, because water solvates the carbocation too strongly to let it react
  2. Bsmaller, because water is a poorer nucleophile than ethanol
  3. Cthe same, because the rate does not depend on the nucleophile
  4. Dgreater, because the more polar and more strongly hydrogen-bonding solvent stabilises the ionic transition state

Answer: D

The rate-determining step is ionisation, which develops charge in the transition state. A more ionising solvent (higher polarity, more hydrogen-bond donation to the leaving ) lowers that barrier. Independence from the nucleophile does not mean independence from the solvent.
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