Assertion (A) : All aliphatic aldehydes give a positive Fehling’s test.
Reason (R) : Aliphatic aldehydes are reduced by Fehling’s reagent.
Reason (R) : Aliphatic aldehydes are reduced by Fehling’s reagent.
Show Hint
Fehling's reagent is an oxidizing agent; it gains electrons and is reduced.
Note that aromatic aldehydes (like benzaldehyde) do not give a positive Fehling's test.
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
The Correct Option is C
Solution and Explanation
• Fehling's test is used to distinguish aldehydes from ketones.
• Aldehydes act as reducing agents in this reaction.
Step 1: Evaluate the Assertion
Aliphatic aldehydes are easily oxidized to carboxylic acids by weak oxidizing agents like Fehling's solution.
This results in the formation of a red precipitate of \( \text{Cu}_2\text{O} \).
Assertion is True.
Step 2: Evaluate the Reason
In Fehling's test, the aldehyde is oxidized to a carboxylate ion.
The \( \text{Cu}^{2+} \) ions in the Fehling's reagent are reduced to \( \text{Cu}^+ \).
The reason states aldehydes are *reduced*, which is chemically incorrect.
Reason is False.
Step 3: Conclusion
Since the assertion is true and the reason is false, the correct code is C.
The final answer is (C).
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