Which of the following can corrode metals like copper and brass?

Sodium hypochlorite, commonly known as bleach, is a powerful oxidizing agent that can indeed corrode metals such as copper and brass. When sodium hypochlorite comes into contact with these metals, it can facilitate oxidation reactions, leading to deterioration over time. This corrosion occurs because sodium hypochlorite breaks down metal surfaces and creates compounds that can further facilitate corrosion.

In contrast, quaternary ammonium compounds are generally considered less aggressive toward metals and are often used as disinfectants due to their lower reactivity. Similarly, 70% ethyl alcohol, while effective as a disinfectant, does not typically cause corrosion of metals like copper or brass. Hydrogen peroxide can also be corrosive in higher concentrations, but it is not as directly harmful to metals as sodium hypochlorite in common cleaning and disinfection contexts.