Which of the following processes of adsorption is endothermic?

Options

A. Adsorption of acetic acid is solution by charcoal.
B. Adsorption of oxalic acid in solution by charcoal.
C. Adsorption of hydrogen on glass.
D. Adsorption of `CO` on tungsten.

Answer

To determine which of the given processes of adsorption is endothermic, we need to analyze each option based on the nature of adsorption involved.

### Step-by-Step Solution:

1. **Understanding Adsorption Types**:
- Adsorption can be classified into two main types: **Physical Adsorption (Physisorption)** and **Chemical Adsorption (Chemisorption)**.
- Physisorption is generally exothermic, meaning it releases heat during the process. This occurs due to weak van der Waals forces.
- Chemisorption, on the other hand, involves the formation of stronger chemical bonds and can be endothermic, meaning it absorbs heat.

2. **Analyzing the First Option**:
- The first option is the adsorption of acetic acid in solution by charcoal.
- In this case, acetic acid acts as the adsorbate and charcoal as the adsorbent.
- Since the interaction is primarily through weak van der Waals forces, this process is classified as physical adsorption, which is exothermic.

3. **Analyzing the Second Option**:
- The second option is the adsorption of auxillic acid in solution by charcoal.
- Similar to the first option, auxillic acid is the adsorbate and charcoal is the adsorbent.
- This process also involves weak van der Waals forces, indicating that it is physical adsorption and thus exothermic.

4. **Considering Other Processes**:
- If there are other processes not mentioned in the transcript, we would need to analyze them similarly. Typically, processes involving strong chemical interactions (like the dissociation of molecules into atoms) may indicate chemisorption, which can be endothermic.

5. **Conclusion**:
- Based on the analysis of the provided options, both processes mentioned (adsorption of acetic acid and auxillic acid by charcoal) are exothermic. Therefore, we need to look for a process involving stronger interactions that could be endothermic.

### Final Answer:
None of the provided options are endothermic. However, if there are other processes involving chemisorption, those could potentially be endothermic.