Question

The Langmuir adsorption isotherm is deduced by assuming that :

• A. the heat of adsorption varies with coverage
• B. the adsorbed molecules interact with each other
• C. the adsorption takes place in multi-layers
• D. the adsorption sites are equivalent in their ability to adsorb the particles

Answer 1

The correct option is D the adsorption sites are equivalent in their ability to adsorb the particles

The Langmuir adsorption isotherm is deduced using the assumption that the adsorption sites are equivalent in their ability to adsorb the particles.

Langmuir adsorption isotherm shows the following characteristics:

1. The surface of the adsorbent is uniform, that is, all the adsorption sites are equivalent.
2. Adsorbed molecules do not interact.
3. Adsorption at all sites occurs through the same mechanism.
4. At the maximum adsorption, only a monolayer is formed. Molecules of adsorbate do not deposit on others, already adsorbed but only on the free surface of the adsorbent.