Assertion (A): F, has lower bond dissociation energy than `Cl_(2)`.
Reason (R): Flourine is more electronegative than chlorine.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is NOT the correct explanation of A
C. A is true but R is false
D. A is false and R is True.

Explanation

To analyze the given assertion and reason, let's break it down step by step:

### Step 1: Understanding the Assertion
The assertion states that F₂ (fluorine gas) has a lower bond dissociation energy than Cl₂ (chlorine gas).

**Hint**: Recall that bond dissociation energy refers to the energy required to break a bond between two atoms in a molecule.

### Step 2: Analyzing Bond Dissociation Energy
Bond dissociation energy is influenced by several factors, including atomic size and electron-electron repulsions. Fluorine atoms are small and have high electronegativity, which leads to significant electron-electron repulsions due to the presence of lone pairs.

**Hint**: Consider how the size of the atoms and the presence of lone pairs affect the stability of the bond.

### Step 3: Evaluating Fluorine's Structure
Fluorine has 7 valence electrons, and when two fluorine atoms bond, they share one pair of electrons. However, each fluorine atom also has three lone pairs of electrons. The repulsion between these lone pairs makes the F-F bond weaker.

**Hint**: Think about how lone pairs can cause repulsion and affect bond strength.

### Step 4: Comparing with Chlorine
Chlorine, on the other hand, has a larger atomic size and can accommodate its lone pairs better due to the presence of 3d orbitals. This reduces the repulsion experienced by the bonding electrons, resulting in a stronger Cl-Cl bond compared to the F-F bond.

**Hint**: Reflect on how the size and electron configuration of chlorine contribute to its bond strength.

### Step 5: Analyzing the Reason
The reason states that fluorine is more electronegative than chlorine. While this statement is true, it does not explain why F₂ has a lower bond dissociation energy than Cl₂.

**Hint**: Consider whether electronegativity directly impacts bond dissociation energy in this context.

### Step 6: Conclusion
Both the assertion and the reason are true statements. However, the reason provided does not correctly explain the assertion. The correct explanation involves the repulsion of lone pairs in fluorine leading to a weaker bond.

**Final Answer**: Both assertion and reason are true, but the reason is not the correct explanation for the assertion.