Which of the following are common water vapor collection materials used for water vapor removal from ambient air?
(A) Calcium sulfate (B) Silica gel (C) Sulfuric acid (D) Activated alumina (E) Anhydrous magnesium perchlorate
Choose the correct answer from the options given below:

Correct option is C

Materials used for water vapor collection are highly effective desiccants (drying agents) that absorb or adsorb moisture from ambient air. Let’s analyze each option:
1. Calcium sulfate (A):
· Used as a desiccant in its anhydrous form, commonly known as "Drierite." It absorbs moisture effectively from the air.
2. Silica gel (B):
· A widely used desiccant with a high surface area, silica gel adsorbs water vapor and is reusable after drying.
3. Sulfuric acid (C):
· Concentrated sulfuric acid is hygroscopic and absorbs moisture from the air. It is often used in laboratory setups for water vapor removal.
4. Activated alumina (D):
· A porous, high-surface-area material that adsorbs water vapor. It is commonly used in air dryers and industrial dehumidifiers.
5. Anhydrous magnesium perchlorate (E):
· Highly effective desiccant for removing water vapor in laboratory applications, often used in gas analysis.
Thus, all the materials listed — (A), (B), (C), (D), and (E) — are effective for water vapor collection and removal.
Information Booster: 1. Applications of Desiccants:
· Industrial use: In air dryers and dehumidifiers.
· Laboratories: For controlling moisture in closed systems.
· Storage: Protecting sensitive items like electronics and pharmaceuticals.
2. Regeneration of Desiccants:
· Some desiccants, like silica gel and activated alumina, can be regenerated by heating to release absorbed moisture.
3. Common Desiccants in Different Applications:
· Silica gel: Widely used in packaging.
· Calcium sulfate: Cost-effective drying agent.
· Magnesium perchlorate: High efficiency in analytical setups.
Additional Knowledge: (A) Calcium sulfate:
· Known commercially as "Drierite."
· Used in drying tubes and gas desiccation.
(B) Silica gel:
· Color-changing silica gel indicates saturation by moisture.
(C) Sulfuric acid:
· Highly corrosive; used cautiously for moisture absorption.
(D) Activated alumina:
· Found in industrial-scale air and gas drying systems.
(E) Anhydrous magnesium perchlorate:
· Effective but expensive; used primarily in laboratory applications.