Question

The major product of the following reaction is:

 

• A.
• B.
• C.
• D.

Hint:

The Cannizzaro reaction is a type of redox reaction where one molecule is reduced to an alcohol, and the other is oxidized to a carboxylate anion. This reaction occurs in aldehydes without an alpha-hydrogen under basic conditions.

Answer 1

The Correct Option is C

The objective is to determine the primary product of the provided reaction. The critical insight is recognizing the aldol condensation occurring, where propanal (CH₃CH₂CH=O) reacts with an excess of formaldehyde (HCHO) under alkaline conditions.

Solution Process:

1. Reactant and Reagent Identification: Propanal and formaldehyde are the reactants, with an alkali serving as the reagent, characteristic of aldol condensation.
2. Aldol Condensation Mechanism: This process yields a β-hydroxy aldehyde or ketone. The alkali abstracts an alpha-hydrogen from propanal, forming an enolate ion.
3. Aldol Product Synthesis: The enolate ion nucleophilically attacks the carbonyl carbon of formaldehyde, creating a β-hydroxy aldehyde intermediate.
4. Dehydration to Final Product: The β-hydroxy aldehyde eliminates water to yield an α,β-unsaturated carbonyl compound.

Outcome: The major product of this reaction is an α,β-unsaturated aldehyde.

Therefore, the principal product of the reaction is depicted in the accompanying image, corresponding to the second selection from the given options.