Question

Explain the difference between aldehydes and ketones by Fehling solution and Schiff reagent.

Hint:

Fehling’s test detects reducing aldehydes, while Schiff’s reagent gives a color change for aldehydes but not ketones.

Answer 1

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.