Assertion : Bond order can assume any value number including zero.
Reason :Higher the bond order ,shorter is bond length and greater is bond energy.

Options

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

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts of bond order, bond length, and bond energy step by step.

### Step-by-Step Solution:

1. **Understanding Bond Order**:
- Bond order is defined as the difference between the number of bonding electrons and the number of anti-bonding electrons, divided by two.
- Mathematically, it can be expressed as:
\[ \text{Bond Order} = \frac{(N_b - N_a)}{2} \]
where \(N_b\) is the number of bonding electrons and \(N_a\) is the number of anti-bonding electrons.

2. **Assertion Evaluation**:
- The assertion states that "Bond order can assume any value including zero."
- For example, in the case of the helium molecule (He2), the bond order is calculated as follows:
- Helium has 2 electrons in the bonding molecular orbital (σ1s) and 2 electrons in the anti-bonding molecular orbital (σ1s*).
- Therefore, the bond order is:
\[ \text{Bond Order} = \frac{(2 - 2)}{2} = 0 \]
- This shows that bond order can indeed be zero, confirming the assertion is **true**.

3. **Reason Evaluation**:
- The reason states that "Higher the bond order, shorter is the bond length and greater is bond energy."
- This statement is based on the relationship between bond order, bond length, and bond energy:
- As bond order increases (e.g., from a single bond to a double bond to a triple bond), the bond length decreases and the bond energy increases.
- For example:
- A single bond (C-C) has a bond order of 1, a double bond (C=C) has a bond order of 2, and a triple bond (C≡C) has a bond order of 3.
- As we move from single to triple bonds, the bond length decreases and the bond energy increases.
- Thus, the reason is also **true**.

4. **Conclusion**:
- Both the assertion and the reason are true.
- However, the reason does not serve as a correct explanation for the assertion. The assertion about bond order being able to be zero is a separate fact and does not depend on the relationship described in the reason.

### Final Answer:
- **Assertion**: True
- **Reason**: True
- **Explanation**: The reason is not the correct explanation of the assertion.

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