Question

Assertion (A): All aliphatic aldehydes give a positive Fehling's test.
Reason (R): Aliphatic aldehydes are reduced by Fehling's reagent.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Fehling’s Test: Aldehyde = reducing agent → oxidized to acid Cu\(^{2+}\) → Cu\(_2\)O (red precipitate)

Answer 1

The Correct Option is C

Step 1: Analyze Assertion (A). Aliphatic aldehydes generally give a positive Fehling’s test by reducing cupric ions to cuprous oxide (red precipitate). \(\Rightarrow\) Assertion is true.
Step 2: Analyze Reason (R). The reason states aldehydes are reduced by Fehling’s reagent. This is incorrect — actually, aldehydes
reduce Fehling’s reagent and are themselves oxidized to carboxylic acids. \[ R{-}CHO \rightarrow R{-}COOH \] \(\Rightarrow\) Reason is false. \[ \therefore \text{Assertion true, Reason false} \]