What are the exceptions regarding concentrations of disinfecting agents?

The correct answer highlights key practical considerations regarding the use of disinfecting agents. A 10% solution of bleach is indeed effective for disinfection, especially for surface cleaning and pathogen elimination. This concentration is often recommended for various cleaning applications, including sanitizing surfaces in healthcare settings or other environments where infection control is essential.

Additionally, the mention of 70% alcohol is significant because, while alcohol-based disinfectants are widely used, their effectiveness can be compromised if they evaporate too quickly. At around 70% concentration, alcohol has an optimal balance of disinfecting action and evaporation rate. This allows sufficient contact time with pathogens, which is crucial for effective disinfection. If the concentration is too high, such as in 100% alcohol, it may evaporate too rapidly, preventing adequate microbial kill.

Understanding these nuances around concentrations helps ensure that disinfection practices are both effective and practical.