What is a common tool used for testing chlorine residual in water?

A colorimeter is a common tool used for testing chlorine residual in water because it measures the intensity of color in a solution, which correlates to the concentration of chemical substances, such as chlorine. When testing for chlorine, a colorimeter can determine the residual amount present by detecting the color change that occurs when specific reagents are added to the water sample. This method is precise and widely used in water quality assessments to ensure safe drinking water and monitor compliance with health regulations.

While pH meters, multimeters, and turbidity meters are important instruments in water quality testing, they serve different purposes. A pH meter measures the acidity or alkalinity of water, a multimeter evaluates electrical properties such as voltage or current, and a turbidity meter gauges the clarity of water by measuring suspended particles. None of these tools are specifically designed for measuring chlorine residuals, making the colorimeter the most appropriate choice for this purpose.