ScienceHideout - 21-5-2012 at 13:10
In a lab activity I did, I used Fehling's solution to test for sugar. When I tested something with no sugar, nothing happened. But, when I tested
something with sugar, I got an orange precipitate.
Now- the problem- when I did a test with nothing at all, the solution decomposed and I got a brown precip.
How do I know if I really have sugar present, or if the solution is just decomposing?
Thanks,
ScienceHideout
Hexavalent - 21-5-2012 at 13:19
Benedict's solution is used for testing for reducing sugars, and gives an orange/brown ppt. when added.
How old were the solutions you used? IME we have always prepared Fehling's solution fresh in our labs.
MR AZIDE - 22-5-2012 at 10:41
Yeah, make up the solution fresh, then that way you know there is no contaminants, which is what i think must ve happened.
Its supposed to go from clear blue alkaline Cu2+ environment to red precipitate of copper(i) oxide while heating, when reducing sugars are present.