Question

Which of the following increases the activation of a solid adsorbent?
(A) polishing the surface of solid adsorbent
(B) subdividing the solid adsorbent
(C) blowing superheated steam through the porous adsorbent
(D) adsorption at very low pressure
(E) all answers are correct

Answer 1

Hint: The surface of a solid can attract and retain the molecules of the phase when substances come into contact. If these molecules remain only at the surface of the solid is absorbent, the particles on adsorbent are adsorbate and the phenomenon is called adsorption.

Complete step by step solution:
The accumulation of molecular species at the surface is named as adsorption, which is a surface phenomenon.
For example, charcoal, colloids, clay, metals in the finely powdered states act as good adsorbents.
The factors influencing of adsorption of gases on solids as follows:
(1) the surface area of adsorbent: the adsorption process is a surface phenomenon. The surface is of the adsorbent is directly proportional to the extent of adsorption. Especially solids like finely grained powdered substances, which have a large surface area exhibit more adsorption.
(2) Effect of pressure: the relationship between pressure and magnitude of adsorption can be expressed by
$a=K{p}^n$ , where a is the amount of gas adsorbed per unit mass, pressure p, K and n are constants depending upon the nature of gas and adsorbent.
(3) Nature of gas: every gas is adsorbed on the surface of any solid because physical adsorption is non-specific. Under certain conditions of temperature and pressure, liquefiable gases like ammonia, water are adsorbed more than gases like hydrogen, nitrogen.

All options are correct. Except for option, A is incorrect because polishing the surface of solid adsorbent does not affect adsorption.

Note: If the molecules are uniformly distributed throughout the solid, this process is absorption, which is completely different from adsorption. For example, when a chalk stick is dipped in ink, the colored surface will be blue. While inside the chalk sticks are white. This is due to absorption. Water vapors adsorbed on calcium chloride is adsorption.