Assertion. Nitrogen is less reactive than molecular oxygen.
Reason. The bond length of `N_(2)` is shorter than that of oxygen.

Options

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

Explanation

To solve the question regarding the assertion and reason about the reactivity of nitrogen compared to molecular oxygen, we can break down the problem into several steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that nitrogen is less reactive than molecular oxygen.
- This means we need to evaluate the reactivity of both nitrogen (N₂) and oxygen (O₂).

2. **Evaluating Reactivity**:
- Reactivity is often related to the stability of the molecule. A more stable molecule is generally less reactive.
- In this context, we need to compare the bond strength and bond order of N₂ and O₂.

3. **Bond Characteristics**:
- Nitrogen (N₂) has a triple bond (N≡N), while oxygen (O₂) has a double bond (O=O).
- The bond order is a measure of the number of chemical bonds between a pair of atoms. For N₂, the bond order is 3, and for O₂, the bond order is 2.

4. **Bond Length and Stability**:
- The bond length is inversely proportional to the bond order. A higher bond order typically means a shorter bond length and greater stability.
- Since N₂ has a bond order of 3, it has a shorter bond length compared to O₂, which has a bond order of 2.

5. **Conclusion on Reactivity**:
- Because N₂ is more stable (due to its shorter bond length and higher bond order), it is less reactive than O₂.
- Therefore, the assertion that nitrogen is less reactive than molecular oxygen is correct.

6. **Analyzing the Reason**:
- The reason given is that the bond length of N₂ is shorter than that of O₂.
- While this statement is true, it does not directly explain why nitrogen is less reactive than oxygen. The reason focuses on bond length rather than the relationship between stability and reactivity.

7. **Final Evaluation**:
- Both the assertion and the reason are correct statements, but the reason does not adequately explain the assertion. Thus, the correct conclusion is that both statements are correct, but the reason is not the correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are correct, but the reason is not the correct explanation of the assertion.