Question

Which of the following gases is readily adsorbed by solid adsorbent?

• A. Cl$_2$
• B. N$_2$
• C. O$_2$
• D. H$_2$

Hint:

Gases with higher critical temperatures are more easily liquefied and thus more readily adsorbed because the intermolecular forces between gas molecules and the adsorbent surface are stronger. Polar gases or gases that can easily be polarized tend to have higher critical temperatures.

Answer 1

The Correct Option is C

Concept:
Adsorption of gases on the surface of a solid depends mainly on the ease of liquefaction of the gas. A gas which is more easily liquefied is adsorbed more readily because stronger intermolecular forces allow gas molecules to stick to the surface more effectively. Ease of liquefaction is measured by critical temperature ($T_c$).

• Higher critical temperature $\Rightarrow$ easier liquefaction
• Easier liquefaction $\Rightarrow$ greater adsorption

Step 1: Compare the given gases
The gases are:

• Hydrogen ($H_2$)
• Nitrogen ($N_2$)
• Oxygen ($O_2$)
• Chlorine ($Cl_2$)

Step 2: Critical temperatures of gases
Approximate critical temperatures: \[ H_2 \approx 33\,K \] \[ N_2 \approx 126\,K \] \[ O_2 \approx 154\,K \] \[ Cl_2 \approx 417\,K \]
Step 3: Identify highest critical temperature
Among all gases: \[ Cl_2 \text{ has the highest critical temperature} \] Hence, chlorine is most easily liquefied.
Step 4: Apply adsorption rule
Since gases with higher critical temperature are adsorbed more strongly: \[ Cl_2 \text{ will be adsorbed maximum} \]
Step 5: Final Answer
The gas most readily adsorbed is: \[ \boxed{Cl_2} \] Quick Tip:
For adsorption questions, remember: \[ \text{Higher } T_c \Rightarrow \text{More adsorption} \]