To determine the concentration of copper II ions in a water sample using polarography, you will need to follow these steps:1. Prepare the water sample: Collect the water sample from the polluted river and filter it to remove any suspended particles. If necessary, dilute the sample to bring the concentration of copper II ions within the range of the polarographic instrument.2. Prepare the polarographic cell: Set up the polarographic cell with a dropping mercury electrode DME as the working electrode, a reference electrode e.g., Ag/AgCl , and an auxiliary electrode e.g., platinum wire . Fill the cell with a supporting electrolyte solution, such as a mixture of potassium chloride KCl and hydrochloric acid HCl .3. Add the water sample: Add a known volume of the filtered and diluted water sample to the polarographic cell. Make sure the sample is well mixed with the supporting electrolyte.4. Perform the polarographic analysis: Apply a potential to the working electrode and record the current response as a function of the applied potential. The potential at which the current response reaches a peak corresponds to the reduction of copper II ions to copper I ions or copper metal. The height of this peak is proportional to the concentration of copper II ions in the sample.5. Calibration: Prepare a series of standard solutions containing known concentrations of copper II ions and perform polarographic measurements on each standard solution. Plot the peak current response as a function of the copper II ion concentration to create a calibration curve.6. Determine the concentration of copper II ions in the sample: Use the peak current response obtained from the water sample and the calibration curve to determine the concentration of copper II ions in the sample. Don't forget to account for any dilution factors used during the sample preparation.By following these steps, you can accurately determine the concentration of copper II ions in the water sample collected from the polluted river using polarography.