What is the main difference between liquefaction and gas condensation?

The primary distinction between liquefaction and gas condensation lies in their definitions and processes. Liquefaction refers to the transformation of a gas into a liquid state, which can occur due to a combination of both increased pressure and reduced temperature. This process is particularly important in cases where gases like natural gas or refrigerants are converted into liquids for easier storage and transportation.

On the other hand, condensation specifically involves the transition of vapor (which is already in the gaseous state but is often saturated) into liquid as the temperature drops or pressure increases. Essentially, condensation is a specific case or subset of the broader process of liquefaction, wherein a vapor becomes a liquid without the same requirements that may be necessary for gases under varying conditions.

Thus, the third statement accurately describes the broader nature of liquefaction compared to condensation, highlighting that while both processes deal with the gas-liquid transition, liquefaction applies to gases generally, and condensation applies to vapors. Recognizing the difference in these definitions helps clarify the overall understanding of phase transitions in gases and liquids.