Both aldehyde and ketone contain
Active group of aldehyde is and ketone's active group is
Aldehyde and ketone both have similar and difference chemical properties. Aldehyde can be oxidized to carboxylic acid easily while ketone are not.
Due to different active groups, aldehyde and ketone indicate different reactions for same reagent. But sometimes they show same changes (like colour changes) to some reagents.
The best way to identify aldehyde from ketone is checking the oxidizing ability of aldehyde or ketone
Aldehyde are oxidized to carboxylic acids by both strong and mold oxidizing agents.
Aldehyde are oxidized to alcohols by strong oxidizing agents and their colour changes will notify strong oxidizing agents are being reduced.
Tollens reagent is prepared by dissolving AgOH white precipitate in ammonia solution.
When aldehyde is oxidized to carboxylic acid, Ag+ is reduced to Ag which is deposited in the bottom of the test tube. Deposited Ag is shown as a silver mirror.
But we cannot identify formic acid and aldehyde from tollen's reagent.
Below table shows some experiments can be done to identify aldehyde and ketone
Qualitative Analysis for anions and cations for Grade 12 ClassEmission of gases Identify ammonium salts identify d block cations by ammonia solution Identify halides Identify carbonate ions identify chromium compounds Testing for thiosulfate (S2O32-) Testing for phosphate ion