Question

When the temperature is reduced and pressure is increased, the adsorption of a gas on a solid
(A) Decreases
(B) Increases
(C) Remains unaffected
(D) Decreases first and then increases

Answer 1

Hint: Physical adsorption is a simple approach, which attaches the target substance to a chip as a result of hydrogen bonding, van der Waals forces, and hydrophobic interactions. It is also known as Physisorption. Physisorption is also called physical adsorption.

Complete Step by Step Solution:
This is a theory-based question. The theory here used is how the temperature affects the viscosity of the fluid, which involves the kinetic energy of the molecules of the fluid and attraction forces between the molecules of the fluid.

Rise in pressure reduces the volume of gas and thus increases the adsorption of gas molecules. Conversely, a reduction in pressure will cause the removal of gas molecules from the solid surface. Since adsorption is exothermic, the physical adsorption occurs readily at low temperatures and decreases with increasing temperatures (Le-Chatelier’s principle).
Hence the correct option is B.

Note: Physical adsorption phenomenon involves the use of weak Van der Waal forces by means of which gas molecules get adsorbed on a solid surface. It is not specific in nature and hence any gas can be adsorbed onto the surface. Adsorption is the adhesion of ions, atoms, or molecules from a liquid, gas, or dissolved solid to a surface. This process forms a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid.