Hydrogen gas is collected by the ____ displacement of water.

Explanation

To answer the question "Hydrogen gas is collected by the ____ displacement of water," we need to understand the properties of hydrogen gas and how it can be collected.

### Step-by-Step Solution:

1. **Understanding the Properties of Hydrogen**:
- Hydrogen is a colorless, odorless gas that is lighter than air and less dense than water.

2. **Density Comparison**:
...