Final answer:
The analysis of chlorine residual should be performed immediately after sample collection to obtain accurate measurements of the chlorine content at that moment.
Step-by-step explanation:
The analysis of chlorine residual should be performed immediately after sample collection.
Chlorine can react with other substances in the water, such as organic matter, bacteria, and microorganisms, leading to changes in the chlorine residual over time. By analyzing the chlorine residual immediately after sample collection, you can obtain a more accurate measurement of the chlorine content at that particular moment.
For example, if you wait too long to analyze the sample, any chlorine that was initially present may have reacted and decreased, resulting in a lower chlorine residual reading. This could lead to incorrect interpretations or misjudgments regarding the safety or effectiveness of the water treatment process.