JEE Main · 2021 · 24 Feb 2021 · Shift 1 · Surface Chemistry

The Freundlich adsorption isotherm is given by:


where:

• $x$ = mass of adsorbate
• $m$ = mass of adsorbent
• $p$ = equilibrium pressure
• $k$ and $n$ are constants

Taking logarithm on both sides:


This can be written as:


Comparing with the straight line equation $y=mx+c$:

• $y=\log \frac{x}{m}$
• $x=\log p$
• slope $m=\frac{1}{n}$
• intercept $c=\log k$

The slope of the line AB in the graph of $\log \frac{x}{m}$ vs $\log p$ is $\frac{1}{n}$, where $\frac{1}{n}$ ranges from 0 to 1 (which means $n>1$).