1. Two boiling tubes containing 1 ml solution A and 1 ml solution B respectively are prepared. 1ml Benedict’s solution is added to each test tube. Both test tube are heated together in the water bath for two minutes. The result is recorded in Table 1. 2. A few drops of fresh solution A and B are added separately spaced on a white tile. 1-2 drops of iodine solution are added on each solution. Observations are recorded in Table 1. 3. 2 ml of solution B is pipetted into each of four boiling tubes. The tubes are labelled 1, 2, 3and 4 respectively near mouth of tube. 4. Tubes 1 and 2 are placed in a water bath of 37ᵒC.
5. 5 ml of saliva is collected in a beaker.
6. Step 6 and 7 are done approximately at the same time. 4ml of the saliva prepared in step 4 is measured and pipetted 2 ml each into tubes 1 and 4. The contents of the tubes is well-shaken to ensure thorough mixing. 7. 4 ml HCl is measured and pipette 2 ml into each tubes 2 and 3. 8. Incubate tubes 1, 2, 3 and 4 at their respective temperatures as shown in Table 2 for 35 minutes from this moment. 9. 4 more new boiling tube are labelled as: 1’, 2’, 3’ and 4’. 10. After 5 minutes of incubation of tube 1 to 4, 1ml of the content from all these tubes were pipette out into the respectively newly labeled tubes (e.g. 1 into 1’, 2 into 2’ etc). Straightaway, the original tubes (labeled 1 to 4) were placed back into the respective temperature of incubation. 11. The Benedict’s test was performed on the content of tubes 1’ to 4’ by pipetting 2ml of Benedict solution into each tubes and heating them in 95C water bath for 5 minutes. The observation was recorded in Table 2. 12. After 35 minutes, Benedict’s test was carried out with an equal volume of Benedict’s solution which is 1ml for each tube. The observation was recorded in Table 2.
| Observations| Conclusions|
Solution A| Benedict’s test:Brick-red precipitate was formed in the solution. The colour of the solution changed...