Specimen G is a paste made from a food material. Carry out the following tests to identify the food substances contained in specimen G. Wash the test tube after each use to ensure that the next sample is not contaminated. All tests and observations should be recorded in a table as shown below.
| Test | observation | inference |
(a) (i) Pour 5 cm/(^3/) of specimen G into a test tube and add three drops of sodium hydroxide solution. Shake two test tube. Record your observation. Then add three drops of copper (ii) tetraoxosulphate (VI) solution (CuSO/(_4/)). Shake the test tube. Record your observations and inference (b) Pour 5 cm/(^3/) of specimen G into a test tube and three drops of Sudan IIl. Shake the mixture. Record your observation and inference (d) To another 5 cm/(^3/) of specimen G add four drops of Fehling’s solution. Shake the test tube. Warm the mixture. Record your observation and inference
Explanation
| Test | observation | inference |
|
(a) 5cm of specimen G +3 drops of NaOH solution + 3 drops of CuSO, |
White or creamy suspension, purple or violet colour was was observed |
Protein present |
|
b) 5cm of specimen G + 3 drops Oil present of Sudan Ill and shaken |
Red colour was obseved. |
Oil present |
|
(c) 5cm of specimen G + 3 drops |
Blue-black or black colour was observed | |
|
(d) 5cm of specimen G +3 drops and warmed in the flame |
No colour change or blue colour observed, reddish brown pink or red colour observed |
Reducing sugar is absent. Reducing sugar is present of fehling's solution, shaken |