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JEE Main levelOne or more correct optionsDifficulty 2 of 3o1257

The aromatic aldehyde shown carries a strongly electron-withdrawing group. Compared with benzaldehyde, select the correct statement(s).

  1. AIt adds cyanide faster
  2. BIts hydration equilibrium lies further towards the gem-diol
  3. CIt is less reactive towards nucleophilic addition than 4-methoxybenzaldehyde
  4. DIts carbonyl carbon carries a larger partial positive charge

Answer: A, B, D

The para nitro group withdraws electrons by the -M and -I effects, increasing the partial positive charge on the carbonyl carbon and making it more electrophilic. 4-Nitrobenzaldehyde therefore adds cyanide faster and has a larger hydration constant than benzaldehyde. It is also more reactive, not less reactive, than 4-methoxybenzaldehyde, whose +M group deactivates the carbonyl.
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