Barfoed's Test is a laboratory test used to differentiate between monosaccharides and disaccharides. It involves adding a solution of copper acetate to a sample and heating it. If the sample contains monosaccharides, a red precipitate forms, indicating a positive result. This test is based on the reducing properties of sugars. Monosaccharides can reduce copper ions in the solution, while disaccharides typically do not react under the same conditions. Therefore, Barfoed's Test is useful in carbohydrate analysis and helps identify the type of sugar present in a sample.