BRAINCAKEFehling's and Benedict's Solutions
Fehling's solution and Benedict's solution are both blue, alkaline solutions containing copper(II) ions, Cu2+. In Fehling's solution the Cu2+ ions are held in solution as a complex with tartrate ions; in Benedict's solution they are complexed with citrate ions. Both are used to tell aldehydes apart from ketones.
To do the test, add a few drops of the carbonyl compound to the reagent and warm in a hot water bath.
Aldehyde: the blue solution gives a brick-red precipitate of copper(I) oxide, Cu2O.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Carbonyl Compounds
- Naming Carbonyl Compounds
- Physical Properties of Carbonyls
- Oxidation of Aldehydes
- Tollens' Reagent
- Iodoform Reaction
- 2,4-DNPH Test
- Reduction with LiAlH4
- Reaction with HCN
All 11 lessons in Carbonyl Compounds · All Edexcel A-level Chemistry topics