Transcribed Image Text: REACTIONS OF CARBOHYDRATES
Reagents:Samples:10% glucose, galactose, fructose, xylose, maltose, sucrose, lactose, starch
(5 ml each) ,2 ml Fehling's A, 2 ml Fehling's B, 8 ml Benedict's reagent, 8 ml
Barfoed's reagent, 3 g sodium acetate, 2 g phenylhydrazineHCl
Materials: 12( 20 ml) test tubes, test tube rack, test tube brush, test tube holder, alcohol
lamp, tripod, wire gauze, water bath, (10 ml) graduated cylinder, dropper, stirring
rod, beaker(250 ml), spatula, microscope,7 glass slide, 7 cover slip, watch glass,
platform balance
Procedure:
1. Osazone formation –Mix 3 g sodium acetate and 2 g phenylhydrazineHCL and 14 ml
distilled water. Warm with stirring until solution clears.
Place 1 ml sugar solution (glucose, fructose, galactose, maltose, xylose, sucrose, lactose)
in separate tube. Add 2 ml of the hot solution in each of the sugar solution, stopper with
cotton, mix well and heat in a boiling water bath for 30 minutes. Cool at room
temperature and examine the crystals under the microscope. Draw and compare the
crystals.
2. Fehling's test – mix 2 ml Fehling's A with 2 ml Fehling’s B and add 4 ml of water. Boil
the solution for 1 minute. If the solution remains clear blue, place 1 ml of the solution in 8
separate test tubes. Add 5 drops of the sugar solution (glucose, fructose, galactose, xylose,
maltose, lactose, sucrose, starch)in separate test tubes. Place the tubes in a boiling water
bath for another 2 minutes and note the formation and color of precipitate.
3. Benedict's test – place 1 ml of Benedict's reagent in 8 separate test tubes. Add 5 drops of
the sugar solution (use all 8 samples) in separate tubes. Place in a boiling water bath for 2
minutes. Cool and observe formation and color of precipitate.
4. Barfoed's test – place 1 ml Barfoed's reagent in 8 separate tubes. Add 5 drops of the
sugar solution (use all 8 samples) in separate tubes. Place in a boiling water bath for 5
minutes. Cool and observe formation and color of precipitate.