Detection of carbohydrates
Approximately 2 mg of methanolic extract was shaken with 10ml of water in attest tube, filtered and the filtrate was concentrated. To the filtrate 2 drops of freshly prepared 20% alcoholic solution of α- naphthol was added. 2 ml of conc. sulphuric acid was added so as to form a layer below the mixture. Red-violet ring appeared, indicating the presence of carbohydrates which disappeared on the addition of excess of alkali.