Assertion (A): Bond energy of CI-CI bond is more than F-F bond.
Reason (R ): Shorter the bond length, stronger the bond, more is the bond energy.

Explanation

To solve the question regarding the assertion and reason provided, we will analyze each part step by step.

### Step 1: Analyze the Assertion (A)
The assertion states that the bond energy of the Cl-Cl bond is more than that of the F-F bond.

- **Bond Energy of Halogens**: The bond energies of the halogen diatomic molecules (F2, Cl2, Br2, I2) follow a specific trend. Generally, the bond energy decreases as we move down the group from fluorine to iodine.
- **Comparison of Cl-Cl and F-F**: The bond energy of Cl-Cl is indeed higher than that of F-F. This is because, although fluorine has a shorter bond length, the bond energy is also influenced by the repulsion between the lone pairs of electrons on the fluorine atoms, which weakens the bond.

**Conclusion for Step 1**: The assertion is correct.

### Step 2: Analyze the Reason (R)
The reason states that "shorter the bond length, stronger the bond, more is the bond energy."

- **Bond Length and Bond Energy Relationship**: Generally, it is true that shorter bond lengths correspond to stronger bonds, which typically means higher bond energies. However, this relationship can be affected by other factors, such as electron repulsion.
- **Specific Case of F-F Bond**: In the case of the F-F bond, although it has a shorter bond length than the Cl-Cl bond, the bond energy is lower due to significant inter-electronic repulsions between the lone pairs of electrons on the two fluorine atoms.

**Conclusion for Step 2**: The reason is not entirely accurate in this context because it does not account for the influence of electron repulsion on bond strength and energy.

### Final Conclusion
- The assertion (A) is correct: The bond energy of Cl-Cl is indeed more than that of F-F.
- The reason (R) is not a correct explanation for the assertion because it overlooks the role of inter-electronic repulsions in the F-F bond.

### Final Answer
Assertion (A) is true, and Reason (R) is false. Therefore, the correct answer is that the assertion is correct but the reason is not a valid explanation for the assertion.

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