Polarography is an electroanalytical technique that measures the current-voltage relationship of a redox-active species in this case, the reducing agent in a solution. It involves applying a potential sweep to a working electrode usually a dropping mercury electrode that is immersed in the solution containing the analyte. The current generated due to the reduction or oxidation of the analyte is measured, and the resulting current-voltage curve polarogram is used to determine the concentration of the reducing agent.Here's how the concentration of a reducing agent can be quantified using polarography:1. Prepare a series of standard solutions with known concentrations of the reducing agent.2. Record the polarograms for each standard solution by applying a potential sweep and measuring the resulting current.3. Identify the half-wave potential E1/2 on each polarogram, which corresponds to the potential at which half of the maximum current is observed. The half-wave potential is characteristic of the reducing agent and is used to confirm its identity.4. Plot the peak current ip as a function of the concentration of the reducing agent for the standard solutions. This will generate a calibration curve.5. Measure the polarogram of the unknown solution containing the reducing agent and determine its half-wave potential and peak current.6. Use the calibration curve to find the concentration of the reducing agent in the unknown solution based on its peak current.Several factors can affect the accuracy of the polarographic measurement:1. Temperature: Temperature can affect the diffusion coefficient of the analyte, the viscosity of the solution, and the redox potential. It is essential to maintain a constant temperature during the experiment.2. Supporting electrolyte: The presence of a suitable supporting electrolyte is crucial to minimize the migration current and maintain a constant ionic strength. The choice of electrolyte should not interfere with the redox reaction of the analyte.3. Electrode surface: The cleanliness and condition of the working electrode can affect the accuracy of the measurement. A dropping mercury electrode provides a fresh surface for each drop, but other electrodes may require cleaning and polishing.4. Stirring: Proper stirring of the solution is necessary to ensure a uniform concentration of the analyte near the electrode surface. Inadequate stirring can lead to inaccuracies in the measured current.5. Oxygen interference: Oxygen can be reduced at the electrode surface, leading to an additional current that may interfere with the measurement. Deoxygenating the solution by purging with an inert gas e.g., nitrogen can help minimize this interference.6. Adsorption: Adsorption of the analyte or other species on the electrode surface can alter the current-voltage relationship and affect the accuracy of the measurement. Careful selection of the electrolyte and experimental conditions can help minimize adsorption effects.By carefully controlling these factors and using appropriate calibration procedures, polarography can be a reliable and accurate method for quantifying the concentration of a reducing agent in a solution.