To determine the concentration of chloride ions in a sample of water collected from a swimming pool using an ion-selective electrode, you need to follow these steps:1. Calibration: First, you need to calibrate the ion-selective electrode using standard solutions with known concentrations of chloride ions. Typically, you would use at least two standard solutions, such as 10 ppm parts per million and 100 ppm. Measure the voltage mV produced by the electrode in each standard solution and plot a calibration curve voltage vs. concentration or use the data to determine the slope and intercept of the calibration line.2. Sample preparation: Collect a representative sample of water from the swimming pool. It's important to ensure that the sample is well-mixed and free of any debris or contaminants that could interfere with the measurement. If necessary, filter the sample through a 0.45 m filter to remove any particulate matter.3. Measurement: Immerse the ion-selective electrode in the swimming pool water sample and allow it to equilibrate. Record the voltage mV produced by the electrode.4. Calculation: Using the calibration curve or the equation of the calibration line, determine the concentration of chloride ions in the swimming pool water sample based on the measured voltage. If you have a linear calibration curve, you can use the following equation:Concentration ppm = Measured voltage - Intercept / SlopeKeep in mind that the accuracy and precision of the measurement will depend on the quality of the calibration, the performance of the ion-selective electrode, and the presence of any interfering ions or substances in the sample.