Question:
Explain the difference between aldehydes and ketones by Fehling solution and Schiff reagent.
Explain the difference between aldehydes and ketones by Fehling solution and Schiff reagent.
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Fehling’s test detects reducing aldehydes, while Schiff’s reagent gives a color change for aldehydes but not ketones.
Updated On: Mar 5, 2025
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Solution and Explanation
Step 1: Fehling’s Test:
- Aldehydes reduce Fehling’s solution (blue) to a red precipitate of Cu\(_2\)O.
- Ketones do not react.
\[
R-CHO + 2Cu^{2+} + 5OH^- \rightarrow R-COO^- + Cu_2O + 3H_2O
\]
Step 2: Schiff’s Test:
- Aldehydes turn Schiff’s reagent pink/magenta.
- Ketones do not react.
Step 3: Conclusion:
- Aldehydes give positive tests in both reactions.
- Ketones give negative results.
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