What is the weight per gallon of the sodium hypochlorite solution used in these dosage calculations?

• A. 9.5 lb/gal
• B. 10.34 lb/gal
• C. 11.0 lb/gal
• D. 12.0 lb/gal

Answer: (B)

Weight per gallon is the density of the sodium hypochlorite solution, used to convert a volume of chemical into pounds for dosing calculations. When you dose water, the amount of disinfectant is often worked out in pounds of chemical, so you multiply the volume you’ll add by pounds per gallon to get the actual mass being introduced. The value 10.34 lb/gal comes from the specific product’s concentration and density, and it ensures that one gallon of this solution delivers the intended amount of disinfectant. Different strengths would have different pounds-per-gallon, so always use the density for the product you’re using.