Which of the following gases is NOT classified as an F-Gas?

The correct answer is methane (CH4) because it is not classified as a fluorinated gas (F-Gas). F-Gases are typically compounds that contain fluorine as part of their molecular structure, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These gases are often used in applications like refrigeration, air conditioning, and insulation due to their properties, but they also have a significant impact on climate change when released into the atmosphere.

In contrast, methane is a naturally occurring greenhouse gas that is primarily produced through biological processes in environments such as wetlands and landfills or through anthropogenic activities like agriculture and fossil fuel extraction. It does not contain fluorine and, therefore, does not fall under the F-Gas classification, which specifically pertains to synthetic gases containing fluorine. This distinction is critical when discussing regulations and environmental impacts of different gases.