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: Understanding the Cannizzaro Reaction
The Cannizzaro reaction involves the disproportionation of non-enolizable aldehydes (aldehydes without alpha-hydrogens) in the presence of a strong base (alkali). This reaction produces an alcohol and a carboxylic acid.
Step 2: Understanding Aldol Condensation
Aldol condensation occurs in aldehydes and ketones that possess at least one $\alpha$-hydrogen in the presence of alkali or acid. It leads to the formation of $\beta$-hydroxy aldehydes or ketones, which can further dehydrate to form $\alpha,\beta$-unsaturated carbonyl compounds.
Step 3: Evaluating the Statements
Statement (A): This is true. The Cannizzaro reaction is given by aldehydes without $\alpha$-hydrogen in the presence of alkali.
Statement (B): This is true. Aldol condensation is given by aldehydes in the presence of alkali or acids.
Statement (C): This is also true. Aldol condensation can occur in the presence of acids or bases. In an acidic medium, the enol form of the carbonyl compound reacts with another carbonyl compound to give aldol condensation products.
Statement (D): Since all the given statements are true, none of them is false.
Step 4: Conclusion
Since all the statements are correct, the false statement does not exist. Thus, option (D) "None of the above" is the correct answer. Final Answer: The correct answer is (D) None of the above.