Assertion : 22.4 L of `N_(2)` at NTP and 5.6 L `O_(2)` at NTP contain equal number of molecules.
Reason : Under similar conditions of temperature and pressure all gases contain equal number of molecules.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Analyze the Assertion
The assertion states that 22.4 L of \( N_2 \) at NTP and 5.6 L of \( O_2 \) at NTP contain equal numbers of molecules.

1. **Calculate the number of moles of \( N_2 \)**:
\[ \text{Number of moles of } N_2 = \frac{\text{Volume}}{22.4 \, \text{L}} = \frac{22.4 \, \text{L}}{22.4 \, \text{L}} = 1 \, \text{mole} \]

2. **Calculate the number of moles of \( O_2 \)**:
\[ \text{Number of moles of } O_2 = \frac{5.6 \, \text{L}}{22.4 \, \text{L}} = \frac{5.6}{22.4} = \frac{1}{4} \, \text{mole} = 0.25 \, \text{mole} \]

3. **Compare the number of moles**:
- \( N_2 \) has 1 mole.
- \( O_2 \) has 0.25 moles.

Since 1 mole is not equal to 0.25 moles, the assertion is **false**.

### Step 2: Analyze the Reason
The reason states that under similar conditions of temperature and pressure, all gases contain equal numbers of molecules.

1. **Understand Avogadro's Law**:
- Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain equal numbers of molecules.

This statement is **true** because it is a fundamental principle in chemistry.

### Conclusion
- The assertion is **false**.
- The reason is **true**.

Thus, the correct answer to the question is that the assertion is false, but the reason is true.

### Final Answer
- Assertion: False
- Reason: True