Sodium hypochlorite is commonly used at a concentration of what percentage in household bleach?

• A. 5.25%
• B. 0.5%
• C. 10%
• D. 1%

Answer: (A)

Disinfection effectiveness depends on the amount of active chlorine in the solution, provided by sodium hypochlorite. Household bleach designed for consumer use typically contains about 5.25% sodium hypochlorite. This concentration is strong enough to reliably disinfect common pathogens when used according to the label, yet safe and practical for household handling. Concentrations around 0.5% or 1% are too dilute for effective disinfection, while a much higher concentration like 10% would be overly hazardous for everyday use and not intended for household cleaning. So, 5.25% is the standard, commonly marketed concentration for household bleach.