Question

What are the main differences between physical adsorption and chemical adsorption?

Hint:

Physisorption is weak and reversible, while chemisorption is stronger and generally irreversible.

Answer 1

Step 1: Physical Adsorption (Physisorption).
Physical adsorption, also known as physisorption, is the process in which molecules are held to a surface by weak Van der Waals forces. These forces are non-specific and reversible. Physisorption typically occurs at low temperatures and high pressures and is characterized by the following:
- Weak forces of attraction between adsorbate and adsorbent.
- No significant chemical reaction occurs.
- Reversible in nature.

Step 2: Chemical Adsorption (Chemisorption).
Chemical adsorption, or chemisorption, involves the formation of a chemical bond between the adsorbate and the surface. This type of adsorption is stronger and occurs when the adsorbate molecules interact chemically with the surface. It is characterized by:
- Strong covalent or ionic bonds.
- Occurs at higher temperatures.
- Generally irreversible.
Step 3: Comparison.