Which of the following is an example of absorption?

Options

A. Water on silica gel
B. Water on calcium chloride
C. Hydrogen on finely divided nickel
D. Oxygen on metal surface

Explanation

To determine which of the following is an example of absorption, we first need to understand the difference between absorption and adsorption.

### Step-by-Step Solution:

1. **Define Absorption and Adsorption**:
- **Absorption** is a process where a substance (the adsorbate) penetrates into the bulk of another substance (the adsorbent). This means that the adsorbate is taken up by the entire volume of the adsorbent.
- **Adsorption**, on the other hand, refers to the process where molecules adhere to the surface of a solid or liquid without penetrating into its bulk.

2. **Identify the Examples**:
- Let's consider the examples provided:
- Water on calcium chloride
- Hydrogen on finitioid nickel
- We need to analyze each example to see if it represents absorption or adsorption.

3. **Analyze Each Example**:
- **Water on Calcium Chloride**: When water comes into contact with calcium chloride, it gets absorbed into the calcium chloride, causing it to dissolve and penetrate into the bulk. This is an example of absorption.
- **Hydrogen on Finitioid Nickel**: In this case, hydrogen molecules adhere to the surface of the nickel catalyst without penetrating into its bulk. This is an example of adsorption.

4. **Conclusion**:
- Based on the definitions and analysis, the correct answer is **Water on Calcium Chloride**, as it represents absorption.