The Vanderwaals forces in halogesn increases in the order

Options

A. `F_(2) lt Cl_(2) lt Br_(2) lt I_(2)`
B. `I_(2) gt Br_(2) gt Cl_(2) gt F_(2)`
C. `F_(2) lt Br_(2) lt I_(2) lt Cl_(2)`
D. `Br_(2) lt F_(2) lt Cl_(2) lt I_(2)`

Answer

To determine the order of Van der Waals forces in halogens, we need to analyze the molecular masses of the halogen diatomic molecules: F₂, Cl₂, Br₂, and I₂. The Van der Waals forces are influenced by the molecular mass and surface area of the molecules. Here’s how we can arrive at the correct order step by step:

### Step-by-Step Solution:

1. **Identify the Halogens**: The halogens we are considering are Fluorine (F), Chlorine (Cl), Bromine (Br), and Iodine (I). They exist as diatomic molecules (F₂, Cl₂, Br₂, I₂).

2. **Determine the Molecular Masses**:
- **F₂**: The atomic mass of Fluorine (F) is approximately 19 g/mol. Therefore, the molecular mass of F₂ = 2 × 19 = 38 g/mol.
- **Cl₂**: The atomic mass of Chlorine (Cl) is approximately 35.5 g/mol. Therefore, the molecular mass of Cl₂ = 2 × 35.5 = 71 g/mol.
- **Br₂**: The atomic mass of Bromine (Br) is approximately 80 g/mol. Therefore, the molecular mass of Br₂ = 2 × 80 = 160 g/mol.
- **I₂**: The atomic mass of Iodine (I) is approximately 127 g/mol. Therefore, the molecular mass of I₂ = 2 × 127 = 254 g/mol.

3. **Compare the Molecular Masses**:
- F₂: 38 g/mol
- Cl₂: 71 g/mol
- Br₂: 160 g/mol
- I₂: 254 g/mol

4. **Order the Masses**: Now, we can arrange these halogens in order of increasing molecular mass:
- F₂ < Cl₂ < Br₂ < I₂

5. **Relate Mass to Van der Waals Forces**: The strength of Van der Waals forces increases with increasing molecular mass. Therefore, the order of Van der Waals forces will be the same as the order of molecular masses.

6. **Final Order of Van der Waals Forces**: Based on the increasing order of molecular masses, the order of Van der Waals forces in halogens is:
- F₂ < Cl₂ < Br₂ < I₂

### Conclusion:
The Van der Waals forces in halogens increase in the order:
**F₂ < Cl₂ < Br₂ < I₂**