To solve this problem, follow these steps:1. Gather materials and equipment: You will need a colorimeter, cuvettes, distilled water, a pipette, a volumetric flask, a beaker, a magnetic stirrer, a stirring bar, and the necessary reagents 1,10-phenanthroline and hydroxylamine hydrochloride .2. Prepare the calibration curve: Prepare a series of standard solutions with known concentrations of iron II ions by diluting a stock solution. Add a fixed amount of 1,10-phenanthroline and hydroxylamine hydrochloride to each standard solution. The hydroxylamine hydrochloride reduces any iron III ions to iron II ions, and the 1,10-phenanthroline forms a red-orange complex with the iron II ions. Allow the solutions to react for a few minutes, then measure the absorbance of each standard solution at the wavelength of maximum absorbance usually around 510 nm using the colorimeter. Plot the absorbance values against the concentration of iron II ions to create a calibration curve.3. Prepare the sample: Collect the water sample and filter it if necessary to remove any suspended particles. Measure a known volume of the water sample and transfer it to a volumetric flask. Add a fixed amount of hydroxylamine hydrochloride and 1,10-phenanthroline to the sample, then dilute it to a known volume with distilled water. Allow the sample to react for a few minutes.4. Measure the absorbance of the sample: Fill a cuvette with the prepared sample and measure its absorbance at the same wavelength used for the calibration curve.5. Determine the concentration of iron II ions in the sample: Use the calibration curve to find the concentration of iron II ions in the sample based on its absorbance value. If necessary, adjust the concentration to account for any dilution that occurred during sample preparation.6. Compare the results with the EPA limit: The Environmental Protection Agency EPA has set a secondary maximum contaminant level SMCL for iron in drinking water at 0.3 mg/L or 0.3 ppm . Compare the concentration of iron II ions in your sample with this limit to determine if it meets the EPA's guidelines.7. Report your findings: Present your results in a clear and concise manner, including the calibration curve, absorbance values, calculated concentration of iron II ions, and a comparison with the EPA limit.