Question

At high pressures, Langmuir adsorption isotherm takes the form:

• A. $\frac{x}{m}=\frac{\mathrm{ap}}{1+\mathrm{bp}}$
  
• B. $\frac{x}{m}=\mathrm{ap}$
  
• C. $\frac{m}{x}=\frac{b}{a}+\frac{1}{\mathrm{ap}}$
  
• D. $\frac{x}{m}=\frac{a}{b}$
  

Answer 1

The correct option is D $\frac{x}{m}=\frac{a}{b}$


Langmuir adsorption isotherm may be given as:
$\frac{x}{m}=\frac{aP}{1+bP}$
At high pressure . At high pressure bP >>> 1 So, 1+bP ≈ bP
$\therefore \frac{x}{m}=\frac{aP}{bP}=\frac{a}{b}$