Materials and Equipment:

  

- Data collection system                     - Ring stand

- pH sensor                                      - Parafilm or aluminum foil

- Drop counter with micro stir bar         - Funnel

- Magnetic stirrer                              - Hydrochloric acid, unknown concentration,

                                                        70 mL

  - Buret, 50-mL                                  - Sodium hydroxide (NaOH), standardized

                                                        by student in previous activity, 100 mL^2

 - Graduated pipet with rubber bulb, 25-mL   - Buffers, pH 4 and pH 10, 10 mL

 - Beaker (2), 100-mL                         - Deionized water, 100 mL

- Beaker (2), 25-mL                          -Wash bottle with deionized water

- Clamp, right-angle                          - Cotton swab or tissue

- Clamp, buret

 

Methods:

 

1. Grind a pill in a mortar to a fine powder.

 

2. Weigh out about 1.0 g and wash the powder into a 250 mL Erlenmeyer flask with about 50 mL of water.

 

3. Transfer 100.00 mL of 0.1 M HCL solution with a pipet into the Erlenmeyer flask.

 

 

4. Place the Erlenmeyer flask on a hot plate and while swirling around, boil the solution for about 5 minutes (The solution will remain murky due to other insoluble ingredients in the sample). 

 

 

5. Allow the solution to cool down to room temperature. 

 

6. Transfer the solution into a 240-mL titration jar and wash the Erlenmeyer flask with three small (5 mL) water aliquots into the jar. 

 

7. Start a new experiment on the data collection system.

 

8. Connect a pH sensor and the Rotary Motion sensor to data collection system.

 

9. In DataStudio create a calculated dataset for Volume.

 

10. In DataStudio create a calculated dataset for the first derivative of the pH vs. Volume.

 

11. Display the pH on y-axis and Volume on the x-axis.

 

12. Setup the Titrator pump.

 

13. Rinse the syringe on the Titrator pump.

 

12. Setup the Titrator Accessory.

 

14. Calibrate the pH sensor.

 

15. Add the micro stir bar to the end of the pH sensor.

 

16. Setup the titrant container and replace the cap on the bottle, but not airtight.

 

17. Load the syringe on the pump with the titrant solution.

 

18. Prime the pump on the Titrator. 

 

19. Mount the jar with the sample on the titration accessory (In order to expedite the titration, while a sample is being titrated, prepare two additional samples for titration).

 

20. Turn on the magnetic stirrer at a steady rate.

  

21. Start recording data.

 

22. Press the "Run" button on the Titrator to start the titration.

 

23. Continue the titration past the equivalence point until the pH curve flattens.

 

24. Stop recording data.

 

25. Print the graph.

 

26. Save your experiment and clean up according to your teacher's instructions.

 

27. Clean the syringe in the Titrator.