Florida Drinking Water Operator "B" Practice Test

Which method is commonly used to measure chlorine levels in drinking water?

1. Colorimetric analysis

2. Conductivity testing

3. Filtration method

4. Photoelectric spectrometry

The correct answer is: Colorimetric analysis

The method commonly used to measure chlorine levels in drinking water is colorimetric analysis. This technique involves adding a reagent to a water sample that reacts with chlorine to produce a color change. The intensity of the resulting color is directly proportional to the concentration of chlorine in the sample, allowing for quantification through comparison to a standard curve or using a calibrated colorimeter. Colorimetric analysis is favored for its simplicity, rapid results, and ability to provide reliable measurements even at low concentrations of chlorine. It is particularly advantageous when testing for free and total chlorine, which are essential parameters in assessing water disinfection and quality. While other methods, such as conductivity testing, may measure ionic compounds in water, they are not specific to chlorine levels. Filtration methods might be used to prepare samples or remove particulates but do not measure chlorine directly. Photoelectric spectrometry can measure absorbance in various solutions, but it is not the primary method for direct chlorine measurement and may involve more complex setups and analysis compared to colorimetric analysis.