To quantify the amount of iron present in a given water sample using colorimetry, you can follow these steps:1. Collect the water sample: Take a representative sample of the water you want to analyze.2. Prepare the sample: If the water sample is turbid or contains suspended particles, filter the sample using a suitable filter paper or membrane filter to obtain a clear solution.3. Digestion optional : If the iron in the sample is present in a form that does not react with the colorimetric reagent, you may need to perform a digestion step. This involves adding a strong acid e.g., concentrated HCl or HNO3 to the sample and heating it to convert the iron into a soluble and reactive form.4. Select a suitable colorimetric method: There are several colorimetric methods available for the determination of iron in water samples. Some of the most common methods include: a. 1,10-Phenanthroline method b. Ferrozine method c. Thiocyanate method5. Prepare the calibration curve: Prepare a series of iron standard solutions with known concentrations. Add the appropriate colorimetric reagent to each standard solution and allow the color to develop. Measure the absorbance of each solution at the specified wavelength using a spectrophotometer or colorimeter. Plot the absorbance values against the iron concentrations to obtain a calibration curve.6. Analyze the sample: Add the colorimetric reagent to the water sample and allow the color to develop. Measure the absorbance of the sample at the specified wavelength.7. Calculate the iron concentration: Use the calibration curve to determine the concentration of iron in the water sample based on its absorbance value.8. Report the results: Express the iron concentration in the appropriate units e.g., mg/L or ppm .Remember to perform appropriate quality control measures, such as analyzing blank samples and using certified reference materials, to ensure the accuracy and reliability of your results.