Carbohydrates:
* Benedict's reagent: This solution is used to detect reducing sugars, such as glucose, fructose, and lactose. It contains copper(II) sulfate, sodium carbonate, and sodium citrate. When heated with a reducing sugar, the copper ions are reduced to copper(I) oxide, which forms a brick-red precipitate.
Proteins:
* Biuret reagent: This solution is used to detect the presence of peptide bonds in proteins. It contains copper(II) sulfate and sodium hydroxide. The copper ions react with the peptide bonds to form a violet-colored complex.
Note: While these are two commonly used chemicals, there are other reagents that can be used for qualitative tests. For instance, iodine solution is used to test for starch (a polysaccharide).
