Water Nuggets Practice Exam

Amperometric titration is regarded as the most accurate method for measuring chlorine residual because it directly measures the concentration of chlorine in the water through electrochemical means. This technique uses a specialized electrode that responds to the amount of free chlorine present, allowing for precise quantification. The results are less influenced by other variables and interferences that might affect other methods.

In contrast, DPD is a popular colorimetric method for measuring free and total chlorine but can be subject to interference from other substances in the water, potentially leading to less accurate results. Similarly, while a pH meter is essential for measuring acidity or alkalinity, it does not measure chlorine residual directly, making it unsuitable for this purpose. The jar test, typically used for determining coagulant dosages in water treatment processes, is not designed for measuring chlorine levels specifically and does not provide a direct determination.

Therefore, because amperometric titration provides a direct and interference-resistant measurement, it is the preferred choice for accurately measuring chlorine residual in water samples.