To determine the concentration of chloride ions Cl- in a given solution using an ion-selective electrode ISE , you will need to perform a potentiometric titration. Here's a step-by-step guide on how to do it:1. Gather materials and equipment: - Chloride ion-selective electrode Cl-ISE - Reference electrode e.g., Ag/AgCl electrode - pH/mV meter or ion meter - Magnetic stirrer and stir bar - Beakers - Volumetric pipettes - Calibration standards chloride solutions with known concentrations - Sample solution with unknown chloride concentration - Deionized water2. Prepare the electrodes: - Assemble the chloride ion-selective electrode and reference electrode according to the manufacturer's instructions. - Soak the electrodes in deionized water for a few minutes to hydrate the membrane and reference junction.3. Calibrate the ion-selective electrode: - Prepare a series of calibration standards with known chloride concentrations e.g., 1, 10, and 100 ppm Cl- . It's essential to use at least two standards to create a calibration curve. - Rinse the electrodes with deionized water and blot dry with a soft tissue. - Place the electrodes in the first calibration standard and wait for the reading to stabilize. Record the mV reading. - Repeat the process for each calibration standard. - Plot the mV readings against the logarithm of the chloride concentrations to create a calibration curve. The slope of the curve should be close to the Nernstian slope about -59 mV/decade at 25C .4. Measure the unknown sample: - Rinse the electrodes with deionized water and blot dry with a soft tissue. - Place the electrodes in the sample solution with unknown chloride concentration. Stir the solution gently with a magnetic stirrer. - Wait for the reading to stabilize and record the mV reading.5. Calculate the chloride concentration: - Use the calibration curve to determine the chloride concentration in the unknown sample. Find the corresponding chloride concentration for the mV reading obtained from the sample. - If necessary, correct the concentration for any dilutions made during sample preparation.By following these steps, you can accurately determine the concentration of chloride ions in a given solution using an ion-selective electrode.