Question

Which gas will be adsorbed on a solid to greater extent?
A.A gas having non-polar molecule
B.A gas having highest critical temperature
C.A gas having lowest critical temperature
D.A gas having highest critical pressure

Answer 1

Hint: Gases that liquefy easily have greater intermolecular forces and hence are adsorbed on a solid surface to greater extent.

Complete step by step answer:
The phenomenon of adsorption of gases by solids depends upon:
-Nature of adsorbent: Easily liquefiable gases such as \[N{H_3}\] , \[C{H_4}\] , HCI, \[C{I_2}\] , \[S{O_2}\] , CO etc. are adsorbed more than permanent gases like \[{H_2}\] , \[{O_2}\] , \[{N_2}\] etc.
-Nature of adsorbate: Activated charcoal is the most common adsorbent for easily liquefiable gases. Poisonous gases such as \[C{H_4}\] and CO fall in this group. Therefore, it is used in gas masks. Other gases such as \[{O_2}\] , \[{H_2}\] and \[{N_2}\] adsorb more on metals such as Ni, Pt and Pd.
-Temperature: The increase of temperature should decrease the extent of adsorption
Pressure: At a given temperature the extent of adsorption will increase with the increase of pressure of the gas.
-Activation of the solid adsorbent: Activation of adsorbent means increasing its adsorbing power which can be increased by increasing specific area either by making the surface rough or by breaking the solid into smaller particles.
-A gas having non-polar molecules has weak forces and thus has less chance of being adsorbed on a solid.
-A gas having the highest critical temperature has greater Vander waals forces of attraction attracted to solid surfaces thus greater is the ease of liquefaction. As the critical temperature of the easily liquefiable gases are more than the permanent gases, it follows that higher the critical temperature of the gas, greater the extent of adsorption. Hence, large adsorption will occur.
-A gas having lowest critical temperature has weak intermolecular forces, hence there is less chance of it being adsorbed.
-A gas having highest critical pressure will also lead to less adsorption of gas on a solid surface.

Therefore, the answer is option (B).


Note:

When increasing adsorbing power of the solid adsorbent is done by breaking the solid into smaller particles, particles should not become very small otherwise the interparticle spaces will be too small to allow penetration of gas molecules.