Coulometric titration is an electroanalytical technique used to determine the concentration of a target analyte by measuring the amount of electrical charge required to complete a chemical reaction. In the case of quantifying the amount of copper in a brass sample, the coulometric titration method involves the reduction of copper ions to metallic copper at the working electrode.Here's a detailed procedure for carrying out the coulometric titration method to determine the amount of copper in a brass sample:1. Sample preparation: a. Weigh an accurately known mass approximately 0.1-0.5 g of the brass sample. b. Dissolve the brass sample in a mixture of concentrated nitric acid HNO3 and hydrochloric acid HCl to form a solution containing copper ions Cu2+ . This process may produce toxic fumes, so it should be done in a fume hood.2. Setup the coulometric titration cell: a. The cell consists of a working electrode cathode , a counter electrode anode , and a reference electrode. The working electrode is typically made of platinum, while the counter electrode can be made of platinum or another inert material. The reference electrode is usually a saturated calomel electrode SCE or a silver/silver chloride Ag/AgCl electrode. b. Fill the cell with a suitable electrolyte solution, such as a mixture of potassium chloride KCl and potassium iodide KI . The electrolyte should not react with the copper ions or interfere with the titration process.3. Calibration: a. Prepare a series of standard copper solutions with known concentrations by dissolving a known amount of pure copper in the same acid mixture used for the brass sample. b. Perform coulometric titrations on the standard copper solutions to establish a calibration curve. This curve will relate the amount of electrical charge required to reduce the copper ions to the concentration of copper in the solution.4. Titration of the brass sample: a. Add the brass sample solution to the electrolyte in the titration cell. b. Apply a constant current between the working and counter electrodes. The current should be sufficient to reduce the copper ions in the solution to metallic copper at the working electrode. c. Monitor the potential difference between the working and reference electrodes. The potential will change as the copper ions are reduced, and the endpoint of the titration is reached when the potential stabilizes at a constant value. d. Record the total electrical charge in coulombs required to reach the endpoint of the titration.5. Calculation of copper concentration: a. Use the calibration curve to determine the concentration of copper in the brass sample solution based on the total electrical charge required for the titration. b. Calculate the mass of copper in the brass sample by multiplying the concentration of copper in the solution by the volume of the solution. c. Determine the percentage of copper in the brass sample by dividing the mass of copper by the initial mass of the brass sample and multiplying by 100.This procedure will provide an accurate quantification of the amount of copper in the brass sample using the coulometric titration method.