Which of the following is NOT a common component of natural gas?

The correct answer is identified as propylene. In the context of natural gas, the primary components typically include methane, ethane, and butane. Methane is the main component, making up about 70-90% of natural gas, while ethane and butane are also found in smaller quantities as part of the hydrocarbons present.

Propylene, on the other hand, is a type of olefin or alkene and is not considered a common component of natural gas. It is more often associated with petrochemical processes and is used primarily in the production of plastics and other chemicals. Understanding the composition of natural gas helps in its extraction and processing, and recognizing what does not typically belong in its composition, such as propylene, is key for anyone working in the field.