Benedict’s test

• Reducing sugars• reduce cupric ions to cuprous form and are

converted to sugar acids• blue solution of Cu (II) or Cu+2, is changed to a

brick red precipitate of Copper (I) or Cu+1 oxide, Cu2O.

• Sugars with free aldehyde groups can reduce either cupric ions in alkaline medium to produce red or orange colored precipitate of cuprous ions

Barfoed’s test

• To distinguish between monosaccharides and disaccharides

• Monosaccharides – more reactive reducing agents

• Disaccharides hydrolyze in the presence of an acid to give the individual monosaccharides.

• reduction of copper(II) acetate to copper(I) oxide (Cu2O), which forms a brick-red precipitate