Which of the following statements is incorrect about hydrogen?

Options

A. Hydrogen has one electron in its outermost shell.
B. It is the lightest gaseous element.
C. It is not easily liquefied.
D. It is a strong oxidising agent.

Explanation

To determine which statement about hydrogen is incorrect, let's analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Hydrogen has one electron in its outermost shell.**
- Hydrogen has an atomic number of 1, which means it has 1 electron. The electron configuration of hydrogen is 1s¹, indicating that it has one electron in the K shell (the outermost shell for hydrogen).
- **Conclusion:** This statement is correct.

2. **Statement 2: Hydrogen is the lightest gaseous element.**
- The atomic mass of hydrogen is approximately 1 gram per mole, which is indeed the lowest among all gaseous elements. Therefore, hydrogen is the lightest gaseous element.
- **Conclusion:** This statement is also correct.

3. **Statement 3: Hydrogen is not easily liquefied.**
- Hydrogen has a low critical temperature, which means it cannot be liquefied easily, regardless of the pressure applied. This is a characteristic of gases with low critical temperatures.
- **Conclusion:** This statement is correct.

4. **Statement 4: Hydrogen is a strong oxidizing agent.**
- An oxidizing agent is a substance that can accept electrons or remove hydrogen from another substance. Hydrogen gas, when reacting with compounds like lead oxide, acts as a reducing agent because it removes oxygen from lead oxide, thereby reducing it to lead and forming water.
- **Conclusion:** This statement is incorrect. Hydrogen is not a strong oxidizing agent; it acts as a reducing agent.

### Final Answer:
The incorrect statement about hydrogen is: **"Hydrogen is a strong oxidizing agent."**