Which gas is known for being produced by incomplete combustion of fuels and is sometimes referred to as "the silent killer"?

Carbon monoxide is identified as "the silent killer" due to its colorless, odorless properties which make it particularly dangerous. It is produced during the incomplete combustion of fossil fuels, such as gasoline, natural gas, and wood. Incomplete combustion occurs when there is insufficient oxygen for the fuel to burn completely, resulting in the release of carbon monoxide rather than carbon dioxide.

When inhaled, carbon monoxide binds with hemoglobin in the blood more effectively than oxygen does. This can lead to reduced oxygen delivery to tissues and organs, potentially causing symptoms like headaches, dizziness, confusion, and in severe cases, can be fatal. The stealthy nature of carbon monoxide makes it challenging to detect without the use of alarms or detectors, thereby earning its nickname as "the silent killer."

The other gases listed do not share the same characteristics or dangers associated with carbon monoxide regarding incomplete combustion or the immediate health risks posed in such scenarios.