Assertion :- Bond energy of `F_2` is less than `Cl_2`.
Reason :- Bond length of `F_2` is smaller than `Cl_2`.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are False.

Answer

To solve the question regarding the assertion and reason about the bond energy of \( F_2 \) and \( Cl_2 \), we can break it down into the following steps:

### Step 1: Analyze the Assertion
The assertion states that the bond energy of \( F_2 \) is less than that of \( Cl_2 \).

- **Bond energy** is the energy required to break a bond between two atoms.
- In general, smaller atoms tend to have stronger bonds due to closer proximity of their nuclei, but in the case of \( F_2 \), the bond energy is lower than expected due to significant repulsion between the lone pairs of electrons.

### Step 2: Analyze the Reason
The reason provided states that the bond length of \( F_2 \) is smaller than that of \( Cl_2 \).

- **Bond length** is the distance between the nuclei of two bonded atoms.
- While \( F_2 \) does have a shorter bond length than \( Cl_2 \), the presence of three lone pairs on each fluorine atom leads to increased electron-electron repulsion, which weakens the bond despite the short bond length.

### Step 3: Conclusion on Assertion and Reason
Both the assertion and the reason are true. However, the reason does not correctly explain the assertion.

- The bond energy of \( F_2 \) is lower than that of \( Cl_2 \) primarily due to the repulsion between the lone pairs in \( F_2 \), not merely because of the bond length.

### Final Answer
- The assertion is true, and the reason is also true, but the reason is not the correct explanation for the assertion.