Question

Identify the correct statements from the following: 
[I.] At constant pressure, physical adsorption decreases with increase in temperature. 
[II.] Enthalpy of physisorption is higher than enthalpy of chemisorption. 
[III.] Gas mask used in coal mines consists of activated charcoal.

• A. I, II, III
• B. I, II only
• C. I, III only
• D. II, III only

Hint:

In adsorption, remember that physical adsorption decreases with increasing temperature, while chemisorption is typically stronger and more temperature-dependent.

Answer 1

The Correct Option is C

Analyzing the given statements: 
Statement I: At constant pressure, physical adsorption decreases with increase in temperature. This is correct because physical adsorption is an exothermic process and its efficiency decreases as the temperature increases.
Statement II: Enthalpy of physisorption is higher than enthalpy of chemisorption. This is incorrect because chemisorption involves a chemical bond formation, which has higher enthalpy compared to physical adsorption.
Statement III: Gas masks used in coal mines consist of activated charcoal. This is correct because activated charcoal is used in gas masks due to its adsorption properties to remove harmful gases. Thus, the correct statements are I and III.