Practical 3 Investigation of Action of Saliva and Hydrochloric Acid in Two Carbohydrate Solution |
Objective:
1. To show the action of saliva in two carbohydrate solutions. 2. To show the action of hydrochloric acid in two carbohydrate solutions. Apparatus & Equipment’s:
Boiling tubes Metal test tube racks Beaker Graduated plastic dropper Water bath,~37°C Water bath,~95°C Stop watch Test tube holder Materials:

Carbohydrate solution A Carbohydrate solution B Benedict’s solution 3M Hydrochloric acid 3M Sodium hydroxide Procedures: 1. Prepared two boiling tubes with containing 1 ml solution A and 1 ml solution B respectively. 1 ml Benedict’s solution was added to each tube and heated both tubes together in the (~95°C) water bath for two minutes. Then, recorded the results in table 1.

2. Added a few drops of fresh solution A and B separately spaced on a white tile. On each solution, added 1-2 drops of iodine solution and mixed with pen cover. Recorded your observations in the table 1.

3. Pipetted 2 ml solution B into each of four boiling tubes. The tubes were labelled 1, 2, 3 and 4 respectively near mouth of tube. Labelled your group name.

4. Placed tubes 1 and 2 in a water bath of ~37°C.

5. Salivated into a small beaker until it reached about 5 ml.

6. At the same time, step (6) and (7) was to be done approximately. Measured out 4 ml of the saliva prepared in step (4) and pipetted 2 ml each into tubes 1 and 4. The contents of the tubes shook well to ensure through mixing.

7. Measured out 4 ml HCL and pipetted 2 ml each into tubes 2 and 3.

8. Let tubes 1, 2, 3,and 4 incubated at their respective temperatures (see Table 2) for 35 minutes from this moment.

9. Labelled 4 more new boiling tubes as follows: 1’, 2’, 3’ and 4’.

10. After 5 minutes of incubation of tubes 1 to 4, poured out about half of the contents from all these tubes into