Question

Is anyone familar with the equilibrium reactions that convert the ketone group of fructose into an aldehyde group so fructose give a positive Fehling's Test? I know it will as we received so in class but not sure how the reaction takes place.

Answer 1

It's explained at this site. Scroll down to the first paragraph under Figure 2 (about 60% down the page). Fructose is converted to glucose and mannonse under th alkaline conditions of the Fehling's test solution.

Answer 2

I didn't post the site. Here it is.
http://www.chemie.uni-regensburg.de/Organische_Chemie/Didaktik/Keusch/D-Fehling-e.htm

Answer 3

DrBob,

Does Figure 2 demonstrate that Fructose is giving a positive result (as an aldose)even though it has been converted to glucose and manose? Thanks for the clarification.