Final answer:
The chemical tests indicate the presence of starch, as confirmed by the blue-black iodine test, and protein, confirmed by the violet color in the Biuret test. The Benedict’s test and the paper test suggest the absence of significant amounts of reducing sugars and lipids, respectively.
Step-by-step explanation:
Identifying organic molecules in a solution involves performing chemical tests that indicate the presence of specific types of compounds. The Benedict’s test, which yielded a pale blue result, is typically used to test for reducing sugars like glucose. However, since the result was a pale blue rather than the orange or red precipitate expected for glucose, it does not indicate the presence of significant amounts of reducing sugars.
The iodine test gives a characteristic blue-black color in the presence of starch. This result indicates that starch is present in the solution, as the iodine binds to the helical structure of amylose in starch, causing the color change. Lastly, the Biuret test produces a violet color if proteins are present in the solution due to the test reagent reacting with peptide bonds. The violet color observed confirms the presence of proteins.
For the last test, a paper test, if a lipid such as a fat or oil was present, a translucent spot would remain on the paper even after it dries; however, the spot dries completely in the scenario described, suggesting there are no significant amounts of lipids in the solution.
Always remember the safety precautions when performing such tests, including wearing goggles to protect your eyes from chemicals and heat.