Question

Identify the gas which is readily adsorbed by activated charcoal?

• A. ${\mathrm{N}}_2$
• B. ${\mathrm{O}}_2$
• C. ${\mathrm{SO}}_2$
• D. ${\mathrm{H}}_2$

Answer 1

The correct option is C

${\mathrm{SO}}_2$

Explanation:

Adsorption: The process adsorption can be defined as a phenomenon of attracting and retaining the molecules of a substance on the surface of a liquid or a solid which results in a higher concentration of molecules on the surface.

• The substance which is getting adsorbed on the surface of a liquid or solid is known as adsorbate and on which surface adsorption is taking place is known as adsorbent.
• The factors that affect the process adsorption are the nature of adsorbate, the nature of adsorbent, pressure, temperature, etc.
• An adsorbent gas with a high critical temperature is more likely to be adsorbed easily than a gas with a low critical temperature.
• The critical temperature of the given gases at NTP is given below:

Gas	Critical temperature in kelvin$\left(\mathrm{K}\right)$
Hydrogen$\left({\mathrm{H}}_2\right)$	$33.2$
Nitrogen $\left({\mathrm{N}}_2\right)$	$126$
Sulphur dioxide$\left({\mathrm{SO}}_2\right)$	$430$
Oxygen$\left({\mathrm{O}}_2\right)$	$154.6$

• The gases in the increasing order of critical temperature is ${\mathrm{H}}_2<{\mathrm{N}}_2<{\mathrm{O}}_2<{\mathrm{SO}}_2$.
• Thus, for the adsorbent like charcoal, the of adsorption of these gases will be ${\mathrm{H}}_2<{\mathrm{N}}_2<{\mathrm{O}}_2<{\mathrm{SO}}_2$.
• The ${\mathrm{SO}}_2$ gas has the highest critical temperature and therefore, ${\mathrm{SO}}_2$ readily adsorbed by activated charcoal

Hence option C is correct.