For HCH, which of the following ranges represents available chlorine content?

• A. 30%-40%
• B. 65%-70%
• C. 10%-20%
• D. 80%-90%

Answer: (B)

Available chlorine content is the portion of chlorine in a disinfectant that is actually available to react and disinfect. For calcium hypochlorite products used as HCH, the typical available chlorine content is about 65% to 70%. This high percentage reflects that the solid compound itself provides a large amount of chlorine that can be released to the water for disinfection.

So, the range around sixty-five to seventy percent best matches how HCH is formulated. Other ranges like 30–40% or 10–20% would be too low for calcium hypochlorite solids, and 80–90% is not a standard, stable specification for these products.