The amount of gas adsorbed on charcoal increases with :-

Options

A. (a)Temperature & pressure
B. (b)Temperature & decreases with pressure
C. (c)pressure & decreases with temperature
D. (d)None

Answer

To solve the question regarding the factors affecting the amount of gas adsorbed on charcoal, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Adsorption**:
- Adsorption is the process where gas molecules adhere to the surface of a solid (in this case, charcoal). This is different from absorption, where substances are taken up into the volume of another substance.

2. **Factors Affecting Adsorption**:
- The amount of gas adsorbed on charcoal is influenced by two main factors: **pressure** and **temperature**.

3. **Effect of Pressure**:
- According to the adsorption isotherm (specifically, the Freundlich or Langmuir isotherm), as the pressure of the gas increases, the amount of gas adsorbed on the charcoal also increases. This is because higher pressure means more gas molecules are available to collide with and adhere to the surface of the charcoal.
- Therefore, we can conclude that **increased pressure leads to increased adsorption**.

4. **Effect of Temperature**:
- The nature of physical adsorption is such that it is exothermic (releases heat). As temperature increases, the kinetic energy of gas molecules also increases, which makes it harder for them to be adsorbed onto the surface of the charcoal. Thus, higher temperatures result in decreased adsorption.
- Consequently, we can conclude that **increased temperature leads to decreased adsorption**.

5. **Final Conclusion**:
- The amount of gas adsorbed on charcoal increases with **increased pressure** and **decreases with increased temperature**. Therefore, the correct answer to the question is that the amount of gas adsorbed on charcoal increases with **increased pressure**.