03. Schiff‘s Reaction Test: If the carbonic compound is added to the schiff reagent, it exhibits a pink color, indicating the presence of aldehyde group.
04. Tollen reagent test: shows the presence of aldehyde group if the carbonic compound is obtained with a silver mirror when heated with tollen reagent.
05. Fehling solution test: If the carbonic compound gets red color on heating with fehling solution then it shows the presence of aldehyde group.
If a compound gives positive results in all the above tests then it is an aldehyde. If a compound gives positive results in Test no. 1 and 2 and negative in Test no. 3, 4 and 5, then it is a ketone.