The adsorption of hydrogen by palladium is commonly known as ______.

Explanation

To solve the question, we need to identify the term that describes the adsorption of hydrogen by palladium. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Concept of Adsorption
- **Definition**: Adsorption is a surface phenomenon where molecules adhere to the surface of a solid or liquid. This is different from absorption, where a substance is taken up into the volume of another substance.

### Step 2: Identify the Material Involved
- **Material**: In this case, the material is palladium, which is a metal known for its ability to adsorb hydrogen gas.

### Step 3: Recognize the Specific Term for Hydrogen Adsorption on Palladium
- **Specific Term**: The adsorption of hydrogen by palladium is specifically referred to as "occlusion." This term is used to describe the process where hydrogen atoms are trapped within the palladium lattice.

### Step 4: Conclude the Answer
- **Final Answer**: Therefore, the adsorption of hydrogen by palladium is commonly known as **occlusion**.

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