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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3co230

The aromatic aldehyde shown is heated with excess methanal (formaldehyde) in concentrated NaOH (crossed Cannizzaro). Which statements are correct?

  1. AThe aromatic aldehyde is converted into the corresponding benzyl alcohol
  2. BMethanal is oxidised to formate
  3. CThe aromatic aldehyde is oxidised to the benzoate while methanal is reduced to methanol
  4. DAldol reaction cannot compete because neither aldehyde has an alpha-hydrogen

Answer: A, B, D

The drawn compound is 4-chlorobenzaldehyde. Neither it nor methanal has alpha-hydrogen, so no aldol occurs. In crossed Cannizzaro the more easily hydrated, more reactive methanal is the hydride donor (oxidised to formate) and the aryl aldehyde is reduced to 4-chlorobenzyl alcohol. So statements 1, 2 and 4 are correct.
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