Question

Which of the following statements is false?

• A. Cannizzaro reaction is given by aldehydes in presence of alkali.
• B. Aldol condensation is given by aldehydes in presence of alkali.
• C. Aldol condensation is given by aldehydes and ketones in presence of acids.
• D. None of the above.

Hint:

- Cannizzaro reaction occurs in aldehydes without $\alpha$-hydrogens in the presence of alkali. - Aldol condensation occurs in aldehydes and ketones with $\alpha$-hydrogens, catalyzed by either alkali or acids.

Answer 1

The Correct Option is D

Step 1: Clarifying the Cannizzaro Reaction
The Cannizzaro reaction describes the disproportionation of non-enolizable aldehydes (those lacking alpha-hydrogens) when exposed to a strong base (alkali). This process yields both an alcohol and a carboxylic acid.
Step 2: Clarifying Aldol Condensation
Aldol condensation occurs with aldehydes and ketones possessing at least one $\alpha$-hydrogen, facilitated by alkali or acid. The outcome is the formation of $\beta$-hydroxy aldehydes or ketones, which can subsequently dehydrate to yield $\alpha,\beta$-unsaturated carbonyl compounds.
Step 3: Evaluating the Statements
Statement (A): Accurate. The Cannizzaro reaction is characteristic of aldehydes without $\alpha$-hydrogen in the presence of alkali.
Statement (B): Accurate. Aldol condensation occurs with aldehydes in the presence of alkali or acids.
Statement (C): Also accurate. Aldol condensation proceeds in the presence of acids or bases. In acidic conditions, the enol form of a carbonyl compound reacts with another carbonyl compound to produce aldol condensation products.
Statement (D): Given that all preceding statements are true, none is false.
Step 4: Conclusion
As all statements are accurate, no false statement exists. Therefore, option (D) "None of the above" is the correct selection.Final Answer: The correct answer is (D) None of the above.