What percentage of chlorine does calcium hypochlorite contain?

Calcium hypochlorite typically contains a chlorine concentration that falls within the range of approximately 60% to 70%. This high chlorine content makes it a powerful chemical for disinfection and water treatment applications. The composition of calcium hypochlorite allows for effective bacterial control and algae prevention in water systems. When considering the options provided, the range of 60%-70% is recognized as the standard for commercial-grade calcium hypochlorite, which is why it is the correct answer.

In contrast, lower percentages such as 20%-30% or 40%-50% do not accurately reflect the concentration found in calcium hypochlorite, which is formulated to have much higher levels of chlorine to meet the disinfection needs in various water treatment processes. The 80%-90% range exceeds the typical market formulations, which do not support practical use and safety standards for handling and application.