Final answer:
Sodium hypochlorite bleach is the best option for decontaminating bench tops contaminated with the AIDS virus due to its oxidizing properties and effectiveness in inactivating a wide range of microbes, including viruses.
Step-by-step explanation:
The best choice for decontaminating bench tops contaminated by the AIDS virus is sodium hypochlorite bleach. This is because bleach is an effective chemical disinfectant that works by oxidizing cellular components. It is typically used in healthcare settings for disinfecting surfaces and has the capability to inactivate most microbes, including viruses such as HIV. Although alcohols like ethyl alcohol can denature proteins and disrupt cell membranes, 100% alcohol is not as effective as a 70% aqueous solution due to rapid coagulation of surface proteins, which prevents thorough penetration into cells. Formalin, which is a solution of the alkylating agent formaldehyde, is a strong disinfectant but is very irritating to living tissues and is carcinogenic, therefore not suitable for routine decontamination of surfaces. Quaternary ammonium compounds can disrupt bacterial membranes, but they are less effective against non-enveloped viruses and may not be the best choice against the AIDS virus.