Question

Which of the following is not the application of adsorption?

• A. Use of SiO$_2$ gel for removing moisture
• B. Use of coconut charcoal to separate inert gases
• C. Use of Al$_2$O$_3$ to separate components of organic mixture in chromatography
• D. Use of CaCl$_2$ for removing moisture

Hint:

Key difference: 1. Adsorption = surface phenomenon 2. Absorption = bulk phenomenon (e.g., CaCl$_2$ dissolving water)

Answer 1

The Correct Option is D

Adsorption involves the accumulation of substances on surfaces. The non-application is:
SiO$_2$ gel: Adsorbs moisture (application)
Coconut charcoal: Adsorbs gases (application)
Al$_2$O$_3$: Used as adsorbent in chromatography (application)
CaCl$_2$: Removes moisture by \textit{absorption} (not adsorption) - forms hydrates
Thus, the correct answer is (4).

Answer 2

Step 1: Understand adsorption.
Adsorption is the process where molecules from a gas or liquid adhere to the surface of a solid or liquid (adsorbent).
It is widely used in various applications such as purification, separation, and catalysis.

Step 2: Common applications of adsorption.
- Use of activated charcoal to remove impurities.
- Use of silica gel to dry gases.
- Removal of poisonous gases.
- Chromatography techniques.

Step 3: Role of CaCl$_2$ in moisture removal.
Calcium chloride (CaCl$_2$) removes moisture by absorption, not adsorption.
It absorbs water molecules into its bulk, forming a hydrate.

Step 4: Conclusion.
Therefore, use of CaCl$_2$ for removing moisture is not an application of adsorption.