CONDUCTIVITY TITRATION PROCEDURE

1. Prepare the solution to be titrated by adding 10 drops of the solution to 30 mL of distilled water in a 50 ml beaker.

2. Prepare the conductivity probe for data collection.

• Plug the conductivity probe into the adapter cable in Channel 1 of the CBL.
• Adjust the toggle switch on the conductivity probe box to 0-200 uS.
• Connect the CBL System to the TI-8X calculator with the link cable using the port on the bottom edge of each unit. Firmly press in the cable ends.

3. Turn on the CBL unit and the TI-8X calculator. Press PRGM and select CHEMBIO. Press ENTER, then press ENTER again to go to the MAIN MENU.

4. Set up the calculator and CBL for conductivity measurement.

• Select SET UP PROBES from the MAIN MENU.
• Enter "1" as the number of probes.
• Select CONDUCTIVITY from the SELECT PROBE menu.
• Enter "1" as the channel number.
• USE the STORED CALIBRATION, unless otherwise directed by your teacher.
• Set the probe range to L 0-100 MG/L, unless otherwise directed by your teacher.

5. Set up the calculator and CBL for data collection.

• Select COLLECT DATA from the MAIN MENU.
• Select TRIGGER from the DATA COLLECTION menu.
• Press ENTER after the conductiviy probe has warmed up 10 seconds.

6. Add one drop of indicator solution to the beaker containing the solution to be titrated.

7. Stir the solution with a glass stirring rod, or the conductivity probe. When you are asked to mix the reaction, follow this procedure.

8. Before adding the titrant, put the conductivity probe into the solution to be titrated and monitor the conductivity value on the CBL screen. Once the conductivity has stabilized, press TRIGGER on the CBL. You have now saved the first data point for this experiment.

9. You are now ready to begin the titration.

10. Add the titrant drop-wise to the beaker, taking note to mix the reaction after each drop and recording the conductivity as in the procedure that follows.

• Select MORE DATA on the calculator after each drop to collect another data point.
• Continue adding titrant solution until the conductivity value reaches a value similar to that found before adding any titrant.

11. Select STOP when done titrating, and QUIT to view data.

12. Dispose of the beaker contents as directed by your teacher. Rinse the conductivity probe and return it to the storage solution.

Graphing

Your conductivity values are stored in List L1. In order to create a titration curve you need to manually enter drop number values in list L2, or use the DROP program.

To set up the graph: