S.NO. | EXPERIMENT | OBSERVATION | INFERENCE |
1 | Action of heat: Heat a small amount of substance in a dry test tube. | A black residue is formed | Presence of carbohydrates |
2 | Action of conc.H2SO4 Take a small amount of sample solution in a dry test tube and add 2ml of conc. H2SO4 | The solution becomes black in color | Presence of carbohydrates |
3 | Molisch’s test: To 2 ml of given sample solution and add 5 drops of Molisch’s reagent. Then slowly add 2ml of conc. H2SO4 along the sides of the test tube. | Violet ring is formed at the junction of two layers | Presence of carbohydrates |
4 | Benedict’s test: To 5ml of Benedict’s reagent, add 8drops of given sample. Boil over a flame for 2 minutes or place in a boiling water bath for three minutes and allow to cool. | An appearance of green, yellow, orange or brick red precipitate. | Presence of reducing sugar like glucose, fructose, lactose and maltose. |
5 | Fehling’s test: To the given sample solution, add fehling’s A & B solution. Boil for 15 minutes on the water bath. | Brick red colour precipitate is formed | Presence of reducing sugars |
6 | Tollen’s Mirror test: To 2ml of tollen’s reagent add 2ml of sugar solution, mix well and boil for 2 minutes | Silver mirror is formed | Presence of reducing sugars |