prac test of glucose

The test for glucose

Benedict's Test

Benedict’s Test For Reducing Sugars

All monosaccharide’s and most disaccharide's will reduce copper (II) sulphate, producing a precipitate of copper (I) oxide on heating, so they are called reducing sugars.
Benedict’s reagent is an aqueous solution of copper (II) sulphate, sodium carbonate and sodium citrate.

experiment

(a) Half fill a beaker with tap water and place it on a tripod and gauze. Heat the water with a Bunsen burner. While waiting for the water to boil, carry on with instructions (b) to (d).

(b) Label four test-tubes 1-4.

1% starch solution into tube 1

10% glucose solution into tube 2
(c) Put 20 mm (depth) of
1% albumen solution into tube 3

water into tube 4


d) To each tube add about 10 mm Benedict's solution.

(e) Place the test-tubes in the beaker of hot water (see Figure on p. 2), and adjust the flame to keep the water just boiling and then copy the table below into your notebook

(f) After about 5 minutes, turn out the flame. Place the four tubes in a test-tube rack and compare the colours. Record the results in the form of a table in your notebook and match the final colours as nearly as possible with crayons.

Solution

Colour change on heating with Benedict’s reagent
Final colour (crayon)
1
1% starch

2
10% glucose

3
1% albumen

4
water