OHST Practice Exam

Which method is commonly used for the purification of air containing gases and vapors?

1. Absorption

2. Adsorption

3. Filtration

4. Neutralization

The correct answer is: Adsorption

The correct answer is based on the method's effectiveness in removing contaminants from the air. Adsorption is a process where gas or vapor molecules stick to the surface of a solid material, often referred to as an adsorbent. This method is particularly useful for purifying air containing a wide range of volatile organic compounds (VOCs) and other gaseous pollutants. Adsorption is distinct in that it works by trapping the impurities on the surface rather than chemically reacting with them, which is a key characteristic of this method. Materials such as activated carbon or silica gel are commonly used as adsorbents due to their high surface area, making them capable of capturing a significant amount of gaseous impurities. In contrast, absorption involves the transfer of a substance from a gas phase to a liquid phase, which is not as effective for certain types of gases or vapors. Filtration generally refers to the removal of particulate matter from air or fluids, and while it can remove some types of contaminants, it does not effectively address gaseous pollutants. Neutralization typically refers to a chemical reaction that renders an acid or base harmless rather than a method designed specifically for air purification. Thus, adsorption stands out as the most suitable method for purifying air with gaseous and