OHST Practice Exam

Which of the following processes converts a vapor into a liquid state in air cleaning?

1. Adsorption

2. Absorption

3. Condensation

4. Combustion

The correct answer is: Condensation

The process that converts a vapor into a liquid state in air cleaning is condensation. This physical process involves cooling a vapor to its dew point, where it loses energy and transforms into a liquid. In air cleaning applications, condensation is crucial for removing water vapor or various pollutants present in the air that can be derived from volatile organic compounds (VOCs), industrial emissions, or even humidity. By efficiently transforming these gaseous substances into liquid, systems can effectively capture and separate them from the air, helping to improve air quality. Adsorption involves attaching molecules of vapor or gas onto a solid surface, while absorption refers to the process in which one substance becomes integrated within another, typically involving a liquid absorbing a gas. Combustion, on the other hand, is a chemical reaction that typically results in the oxidation of materials, producing heat and often harmful emissions, which is not related to the conversion of vapor to liquid in the context of air cleaning. Thus, while all the other options pertain to various processes involving gases and vapors, only condensation specifically addresses the conversion of vapor into liquid.