Moderate

Cannizzaro's reaction is NOT given by:

Correct answer: B. Acetaldehyde

  • A. Formaldehyde
  • B. Acetaldehyde
  • C. Benzaldehyde
  • D. Trimethyl acetaldehyde

Explanation

Cannizzaro's reaction is not given by aldehydes and ketones that have alpha hydrogen (hydrogen next to carbonyl carbon). In formaldehyde, there are no α Hydrogen so it will undergo this reaction. Acetaldehyde has 3 α Hydrogens next to C=O group so it cannot undergo this reaction. In trimethyl acetaldehyde, 3 CH3 groups are attached to α Carbon and no α Hydrogen so it will undergo this reaction. In benzaldehyde, there is benzyl group on α carbon so it does not have α Hydrogen and it will undergo this reaction.

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About Aldehydes and Ketones

Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.

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