Can Seliwanoff test distinguish sucrose and fructose?

Yes, the Seliwanoff test can distinguish sucrose from fructose. The test is based on the reactivity of sugars with resorcinol in the presence of concentrated hydrochloric acid. Sucrose, a disaccharide, does not react quickly and shows a weak or negative result in this test. In contrast, fructose, a monosaccharide, reacts quickly with resorcinol and gives a strong, characteristic red color within a short time, typically 1-2 minutes.