Question

Chemical reaction for presence of carbohydrate in honey

Answer 1

Apparatus:

Test tubes, Test tube stand, Burner, Water Bath.

Chemicals:-

Fehling solution A, Fehling solution B, Ammonium chloride solution, Ammonium oxalate solution, Ammonium phosphate, Conc. Nitric acid, Potassium sulphocyanide solution .

Procedure

1. Test for Potassium:-

2ml of honey is taken in a test tube and picric acid solution is added. Yellow precipitate indicates the presence of K+.

2. Test for Calcium:-

2ml of honey is taken in a test tube and NH4Cl solution and NH4OH solution are added to it. The solution is filtered and to the filtrate 2ml of ammonium oxalate solution is added. White ppt. or milkiness indicates the presence of Ca2+ ions.

3. Test for Magnesium:-

2 ml of honey is taken in a test tube and NH4Cl solution is added to it and then excess of Ammonium phospate solution is added. The side of the testtube is scratched with a glass rod. White precipitate indicates the presence of Mg2+ ions.

4. Test for Iron:-

2ml of honey is taken in a test tube and a drop of conc. HNO3 is added and it is heated. It is cooled and 2-3 drops of Potassium sulphocyanide solution is added to it. Blood red colour shows the presence of iron.

TEST FOR CARBOHYDRATES

1. Fehling`s test :

2mL of honey is taken in a test tube and 1mL each of Fehling`s solution A and Fehling`s solution B are added to it and boiled. Red precipitate indicates the presence of reducing sugars.

2. Tollen`s test:

2-3 mL of aqueous solution of honey is taken in a test tube. 2-3mL of Tollen`s reagent is added. The test tube is kept in a boiling water bath for about ten minutes. A shining silver mirror indicates the presence of reducing carbohydrates.

Conclusion

Ø Potassium is present.
Ø Iron is present.
Ø Calcium is absent.
Ø Magnesium is absent.
Ø Honey contains reducing sugar.