Molisch test is carried out to detect carbohydrates. This involves the reaction of a carbohydrate with concentrated sulfuric acid,H2SO4. The Molisch reagent which is a solution of ?-naphthol in 95% ethanol, dehydrates pentoses to form furfural, a five member ring at the top of the reaction. While at the bottom, the test reagent dehydrates hexoses to form 5-hydroxymethyl furfural. Both furfurals are then react with ?-naphthol to yield a colored product. A formation of purple ring between the layers indicates a positive result.
In this experiment, sample A showed a positive result where the purple ring can be seen. We can say that sample A is a carbohydrate. Meanwhile in sample B and C, both showed similar result at which the bottom layer is purple colored and on top is cloudy. In sample D, the above layer is slightly cloudy while the bottom is green in color. The last sample is the distilled water, indicated as the negative control, resulted in greenish color. It gave negative result because it is not a carbohydrate.