Question

Freundlich adsorption isotherm gives a straight line on plotting:
A. ${\dfrac{x}{m}}\text{ }vs\text{ }P$
B. $\log(\dfrac{x}{m}) \text{ vs P}$
C. $\log(\dfrac{x}{m}) \text{ vs logP}$
D. ${\dfrac{x}{m}\text{ }vs\dfrac{1}{P}}$

Answer 1

Hint: As we know adsorption isotherm is a curve that expresses the variation in the amount of gas which is absorbed by the adsorbent with the temperature at constant pressure.

Complete step by step answer:
Let us discuss Freundlich adsorption isotherm in brief:
As the name suggests, The Freundlich adsorption isotherm or also known as the Freundlich equation is an empirical relation between the concentration of a solute on the surface of an adsorbent to the concentration of the solute present in the liquid.

Herbert Freundlich gave an expression through which he represented the isothermal variation of adsorption of a gas absorbed on a unit mass solid adsorbent with pressure.
Now let us define adsorbent in brief: Adsorption is the attractive interaction of atoms, molecules or ions of a gas, or liquid to a surface.
Now we will analyze the mathematical expression given for Freundlich adsorption isotherm:
${\dfrac{x}{m}}$=\[k.{{P}^{1/n}}\left( n>1 \right)\]
Where, x = mass of the adsorbed on the mass of adsorbed
              m=mass of adsorbent
k and n =constants depend on the nature of the adsorbent and the gas at a particular temperature.
Now it can also be written as,
$\log(\dfrac{x}{m})$=\[\log k+1/n\operatorname{logP}\]
Hence, the answer for the given question is option (C).
Note: Students should not confuse adsorption with absorption. Both seem similar but they are different. Absorption is a bulk process whereas adsorption is a surface phenomenon. In absorption the particles go into the bulk of the solvent but in adsorption the particles remain stuck to the surface of the solvent.