Describe5 marksChallenge
Four unknown solutions, labelled P, Q, R and S, were tested using Benedict's test (before and after acid hydrolysis), iodine test, emulsion test and biuret test. The results are shown in the table below.
| Test | P | Q | R | S |
|---|---|---|---|---|
| Benedict's test (before hydrolysis) | Blue colour remains | Blue colour remains | Brick-red precipitate after 30 s | Blue colour remains |
| Benedict's test (after acid hydrolysis + neutralisation) | Brick-red precipitate after 25 s | Blue colour remains | Brick-red precipitate after 30 s | Blue colour remains |
| Iodine test | Yellow-brown colour | Blue-black colour | Yellow-brown colour | Yellow-brown colour |
| Emulsion test (ethanol + water) | No turbidity | No turbidity | No turbidity | No turbidity |
| Biuret test (NaOH + CuSO4) | Purple colour | Blue colour | Blue colour | Purple colour |
Describe how you would use the results in the table to identify the biological molecules present in each solution.