Question

Favourable adsorption isotherms are those

• A. Which are linear and pass through the origin
• B. Which are concave towards the solid-concentration axis throughout
• C. Which are concave towards the fluid-concentration axis throughout
• D. Which possess one or more points of inflection

Hint:

Favourable adsorption isotherms show that as the concentration of the solute increases, the adsorption increases rapidly initially, but at higher concentrations, it becomes less significant and levels off.

Answer 1

The Correct Option is C

- Favourable adsorption isotherms are characterized by a concave shape towards the fluid-concentration axis.
- This indicates that adsorption increases with concentration initially but tends to level off at higher concentrations. 
Conclusion: 
The correct option is (C) because favourable isotherms are concave towards the fluid-concentration axis.