What type of gas is colorless, odorless, toxic, and has an explosive range of 12%-74.2%?

The correct answer, carbon monoxide, is characterized by several critical attributes that align with the description given in the question. Carbon monoxide is indeed colorless and odorless, making it particularly dangerous as it cannot be detected without specialized equipment. Its toxicity is significant, as carbon monoxide can bind to hemoglobin in the blood, preventing the transport of oxygen throughout the body, which can lead to serious health effects and even death if inhaled in sufficient quantities.

In addition, carbon monoxide has a notably wide explosive range of 12% to 74.2% when mixed with air, meaning it can form explosive mixtures in a variety of concentrations, adding to its risks in confined space environments. This explosive potential, combined with its toxicity and lack of sensory warning features, makes carbon monoxide a critical concern in confined spaces.

The other gases mentioned do not share all of these characteristics. Hydrogen sulfide, for example, is also toxic and can have a rotten egg odor, which makes it detectable and somewhat less hazardous in terms of unnoticed exposure compared to carbon monoxide. Methane is colorless and odorless but is primarily known as a flammable gas rather than a toxic threat like carbon monoxide. Sulfur dioxide, while also colorless, has a pungent smell and