Which disinfectant is considered the strongest among the following?

Chlorine gas is considered the strongest disinfectant among the options provided. As a gas, chlorine has a high reactivity and is effective at killing a wide range of pathogens including bacteria, viruses, and certain types of parasites. Its ability to rapidly penetrate cell walls makes it particularly effective for disinfection.

Chlorine gas dissociates in water to form hypochlorous acid, which is the active disinfecting agent. This mechanism allows chlorine gas to achieve a higher concentration of active disinfectant as compared to chlorine compounds that are in a solid or liquid form, such as sodium hypochlorite and calcium hypochlorite. Even though sodium hypochlorite and calcium hypochlorite release chlorine when dissolved in water, the concentration and immediate efficacy of chlorine gas puts it above these compounds in terms of strength.

Hydrogen peroxide, while also an effective disinfectant, operates through different mechanisms and may not be as potent against certain pathogens when compared to chlorine gas. Thus, chlorine gas stands out as the most powerful disinfectant among the listed options.