Question

In the adsorption of a gas on solid, Freundlich isotherm is obeyed. Thus, if the slope of the plot is zero, then the extent of adsorption is:

• A. directly proportional to the pressure of gas
• B. inversely proportional to the pressure of the gas
• C. independent of the pressure of the gas
• D. proportional to the square of the pressure of the gas

Answer 1

Answer: (C)

independent of the pressure of the gas

Freundlich gave an empirical relationship between the quantity of gas adsorbed by a unit mass of solid adsorbent and the pressure at a particular temperature. The relationship can be expressed by the following equation:
$\frac{x}{m}=K{P}^{1/n}$
On taking logarithm on both sides of the equation,
$log\frac{x}{m}=logK+\frac{1}{n}logP$
Here $\frac{1}{n}$ is slope and if it is zero then adsorption is independent of pressure as $\frac{1}{n}logP=0$