Same chapter3 marksDifficulty: Medium
Arrange acetic acid, chloroacetic acid and trichloroacetic acid in increasing order of acidity and give the reason.
Aldehydes, Ketones and Carboxylic Acids
3 marksDifficulty: Medium
How would you distinguish between an aldehyde and a ketone in the laboratory?
Original Khojo Papers practice question — not from a past board paper.
Answer
Tollens' reagent gives a silver mirror with an aldehyde and no reaction with a ketone. Fehling's solution gives a red precipitate of copper(I) oxide with an aliphatic aldehyde and no reaction with a ketone. Both tests depend on the aldehyde being readily oxidised, which a ketone is not.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Both aldehydes and ketones give an orange precipitate with 2,4-dinitrophenylhydrazine, so that test does not distinguish them.
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