What is the purpose of the 1:10 bleach dilution in disinfection practices?

• A. Cost
• B. Chlorine concentration and evaporation rate
• C. Odor
• D. Color

Answer: (B)

Disinfection relies on the amount of active chlorine available to kill germs. A 1:10 bleach dilution is used to bring the solution to an effective yet safe level of chlorine for general surface disinfection. Starting with a typical 5% sodium hypochlorite, a 1:10 mix yields about 0.5% available chlorine, which is a commonly recommended concentration for disinfecting many pathogens when given sufficient contact time. This concentration is strong enough to inactivate microbes but gentler on skin, eyes, and surfaces, and it reduces strong odors and corrosiveness compared with using straight stock bleach. The dilution also lowers the rate at which chlorine off-gasses, making it safer and more practical to handle in routine cleaning. In short, the 1:10 dilution targets the right balance between effective disinfection and safety, rather than simply focusing on cost, color, or odor alone.