Molisch’s test is a general test for the identification of all carbohydrates (monosaccharide, disaccharide, and polysaccharide) and glycoprotein. In this test conc. sulphuric acid added to the solution which hydrolyzes the all glycosidic linkage in the sugar molecules (disaccharide, and polysaccharide) to yield monosaccharide, which in the presence of an acid get dehydrated to form furfural and its derivatives. This is very reactive, and condenses with α-naphthol to give a purple or violet colored product.