Fehlings solution B

: Fehling’s reagent II for sugars, Potassium sodium tartrate solution, alkaline

: F 1272

: Mix with Fehling’s Solutions No.1 is equal
volumes before use. Fehling’s solution
prepared in accordance with a specification
approved by the British Sugar Corporation
for the determination of invert sugar.

: F 1272 (OTTO) Fehlings solution B - used to distinguish aldehyde vs ketone functional groups. The compound to be tested is added to the Fehling's solution and the mixture is heated. Aldehydes are oxidized, giving a positive result, but ketones do not react, unless they are alpha-hydroxy-ketones. The bistartratocuprate(II) complex oxidizes the aldehyde to a carboxylate anion, and in the process the copper(II) ions of the complex are reduced to copper(I) ions.