Fehling's solution test for aldehydes; using glucose for positive result and starch for control

Fehling's solution test for aldehydes: if aldehyde is added to the solution, on heating it is turning from blue (due to copper (II) ions) to brown or red - precipitate of Cu2O (copper (I) oxide) is formed. Essentially we are testing for extremely good reducing properties of aldehydes, which can reduce even such weak oxidising agent as Cu2+ in alkaline medium. As the result of the reaction aldehyde is oxidised forming carboxilate ion. TUTORING Introductory and Advanced high school Chemistry CBSE, Edexcel, etc inquire at sergei@auroville.org.in