Which discharge constituents may result in explosions when combined in sewers?

The combination of gasoline and hexane in sewers can lead to the formation of explosive mixtures due to their highly volatile and flammable nature. Both substances are hydrocarbons that can produce vapors that are heavier than air, allowing them to accumulate in low-lying areas or confined spaces within the sewer system. If ignited, this mixture can result in an explosion.

Gasoline typically contains a complex mix of hydrocarbons, including alkanes, cycloalkanes, and aromatics, which can readily vaporize and create a flammable atmosphere. Hexane, being a low molecular weight alkane, also has a low flash point and can contribute to the flammability of the mixture.

The other options include substances that, while potentially hazardous, do not necessarily create such explosive conditions when combined in the context of sewer systems. For example, hydrochloric acid and methanol do not produce an explosive reaction, and while carbon dioxide and ethanol have their own risks (such as asphyxiation or flammability), they are not known for explosive reactions in this context. Alkanes and benzene, while flammable, do not react explosively in the same manner as gasoline and hexane when mixed in sewers.

Thus