Only the surface atoms in an adsorbent play an active role in adsorption. These atoms possess some residual force such as van der Waals forces and chemical forces. In the process of adsorption. Weak adsorbate is substituting by strong adsorbete. Activated charcoal used in the gas mask is already exposed to the atmospheric air, so gases and water vapours in air are adsorbed on its surface. When the mask is exposed to chlorine atmosphere, the gases are displaced by chlorine. In general, easily liquefiable gases such as `CO_(2),NH_(3),Cl_(2),` and `SO_(2)` are adsorbed to a greater extent than the elemental gases, e.g., `H_(2),N_(2),O_(2),` He, etc.
Which of the following gases will substitute `O_(2)` from adsorbed charcoal?

Options

A. `Cl_(2)`
B. `N_(2)`
C. `CH_(4)`
D. `N_(2)`

Answer

To determine which gas will substitute O₂ from adsorbed charcoal, we need to analyze the properties of the gases listed in the options and their ability to adsorb onto activated charcoal.

### Step-by-Step Solution:

1. **Understanding Adsorption**:
- Adsorption occurs when gas molecules adhere to the surface of a solid (adsorbent) due to intermolecular forces. The strength of these forces determines how well a gas can be adsorbed.

2. **Identify the Gases**:
- The gases provided in the options are Cl₂ (chlorine), N₂ (nitrogen), CH₄ (methane), and the option "all of the above".

3. **Compare the Gases**:
- **Cl₂ (Chlorine)**: Chlorine is a highly reactive and easily liquefiable gas. It has a strong tendency to adsorb onto surfaces like activated charcoal.
- **N₂ (Nitrogen)**: Nitrogen is an elemental gas and is less likely to be adsorbed compared to more reactive gases. It has weaker intermolecular forces.
- **CH₄ (Methane)**: Methane is a simple hydrocarbon and, while it can be adsorbed, it is not as easily liquefiable as Cl₂ and does not have as strong an adsorption tendency as Cl₂.

4. **Determine Substitution Ability**:
- Since Cl₂ is more easily adsorbed due to its reactivity and ability to form stronger interactions with the charcoal surface, it can effectively displace O₂, which is less strongly adsorbed.

5. **Conclusion**:
- Among the given options, Cl₂ is the gas that will substitute O₂ from adsorbed charcoal due to its higher tendency to adsorb.

### Final Answer:
**Cl₂ (Chlorine)** will substitute O₂ from adsorbed charcoal.