Sugars Flashcards
1
Q
Reducing Sugar
A
- sugars that can donate an electron.
- donates an electron to
reduce copper (ll) ions in
copper sulphate solution,
which is blue
- Cu (ll) ions are reduced to
Cu (l) ions, in red copper
(l) oxide
2
Q
Testing for the presence of sugars
A
- equal volume of benedict’s solution and the solution being tested are boiled.
- if a reducing sugar is present, e.g. glucose, the solution will change colour from blue to brick-red
- described as a qualitative test, as it doesn’t give the actual concentration of the reducing sugar
3
Q
Non-reducing sugars
A
Some disaccharide, e.g. sucrose cannot be detected by the benedict’s solution unless their broken down into their constituent monosaccharides.
4
Q
Testing for a non-reducing sugar
A
-Hydrochloric acid is added to the solution being tested.
- Alkali is added
- Benedict’s solution is added, and the solution is boiled
- If the solution turns red, a non-reducing sugar was initially present.