Potentiometry is a widely used analytical technique for measuring the concentration of ions in a solution. To quantify the concentration of chloride ions in a water sample using potentiometry, you can use a chloride-selective electrode, such as a silver/silver chloride Ag/AgCl electrode. Here is a step-by-step procedure:1. Calibration: Prepare a series of standard chloride solutions with known concentrations. These solutions will be used to create a calibration curve, which will help determine the concentration of chloride ions in the unknown water sample.2. Assemble the potentiometric setup: Connect the chloride-selective electrode Ag/AgCl and a reference electrode e.g., a saturated calomel electrode to a high-impedance voltmeter or a pH/mV meter.3. Measure the potential of standard solutions: Immerse the electrodes in each standard chloride solution, and allow the potential to stabilize. Record the potential in millivolts for each solution. Rinse the electrodes thoroughly with deionized water between each measurement to avoid cross-contamination.4. Create a calibration curve: Plot the measured potentials mV on the y-axis against the logarithm of the chloride concentrations log [Cl-] on the x-axis. The resulting curve should be linear, and its equation can be used to determine the concentration of chloride ions in the unknown water sample.5. Measure the potential of the unknown water sample: Immerse the electrodes in the water sample, and allow the potential to stabilize. Record the potential in millivolts .6. Determine the chloride concentration: Use the equation of the calibration curve to calculate the logarithm of the chloride concentration log [Cl-] in the unknown water sample. Then, convert the logarithm to the actual chloride concentration by taking the antilogarithm 10^log[Cl-] .7. Report the results: Express the concentration of chloride ions in the water sample in the appropriate units, such as mg/L or ppm.Note: It is essential to maintain constant temperature during the measurements, as the potential readings can be affected by temperature variations. Additionally, the presence of interfering ions in the water sample may affect the accuracy of the measurements. In such cases, the use of an ionophore or a complexing agent can help minimize interference.