Which of the following statements is correct ?

Options

A. `ClF_(3)` molecule is bent T-shape
B. In `SF_(4)` molecule, F-S-F equatorial bond angle is `103^(@)` due to lp-lp repulsion
C. In `[IC l_(4)]^(-)` molecular ion, Cl-I-Cl bond angle is `90^(@)`
D. In `OB r_(2)`, the bond angle is less than `OC l_(2)`

Answer

To determine which of the statements regarding the molecular structures and bond angles is correct, we will analyze each statement step by step.

### Step 1: Analyze the first statement about ClF3
1. **Identify the central atom**: Chlorine (Cl).
2. **Count the valence electrons**: Chlorine has 7 valence electrons.
3. **Count the monovalent atoms attached**: There are 3 fluorine (F) atoms attached.
4. **Calculate the steric number** using the formula:
\[ \text{Steric number} = \frac{1}{2} \left( V + M + \text{charge} \right) \]
Here, \( V = 7 \) (from Cl), \( M = 3 \) (from 3 F), and the charge is 0 (neutral molecule):
\[ \text{Steric number} = \frac{1}{2} \left( 7 + 3 + 0 \right) = \frac{10}{2} = 5 \]
5. **Determine hybridization**: A steric number of 5 corresponds to \( sp^3d \) hybridization.
6. **Identify bond pairs and lone pairs**: There are 3 bond pairs (Cl-F) and \( 5 - 3 = 2 \) lone pairs.
7. **Determine molecular geometry**: The presence of 2 lone pairs gives a T-shaped geometry.
8. **Conclusion**: The first statement is correct; ClF3 is indeed T-shaped.

### Step 2: Analyze the second statement about SF4
1. **Identify the central atom**: Sulfur (S).
2. **Count the valence electrons**: Sulfur has 6 valence electrons.
3. **Count the monovalent atoms attached**: There are 4 fluorine (F) atoms attached.
4. **Calculate the steric number**:
\[ \text{Steric number} = \frac{1}{2} \left( V + M + \text{charge} \right) \]
Here, \( V = 6 \), \( M = 4 \):
\[ \text{Steric number} = \frac{1}{2} \left( 6 + 4 + 0 \right) = \frac{10}{2} = 5 \]
5. **Determine hybridization**: A steric number of 5 corresponds to \( sp^3d \) hybridization.
6. **Identify bond pairs and lone pairs**: There are 4 bond pairs and \( 5 - 4 = 1 \) lone pair.
7. **Determine molecular geometry**: The geometry is see-saw due to the lone pair.
8. **Analyze bond angles**: The equatorial bond angle (FSF) is less than 120 degrees due to lone pair-bond pair repulsion, not lone pair-lone pair repulsion.
9. **Conclusion**: The second statement is incorrect.

### Step 3: Analyze the third statement about ICl4^-
1. **Identify the central atom**: Iodine (I).
2. **Count the valence electrons**: Iodine has 7 valence electrons.
3. **Count the monovalent atoms attached**: There are 4 chlorine (Cl) atoms attached.
4. **Account for the charge**: Since it is an anion with a charge of -1, we add 1 electron.
5. **Calculate the steric number**:
\[ \text{Steric number} = \frac{1}{2} \left( V + M + \text{charge} \right) \]
Here, \( V = 7 \), \( M = 4 \), and charge = -1:
\[ \text{Steric number} = \frac{1}{2} \left( 7 + 4 + 1 \right) = \frac{12}{2} = 6 \]
6. **Determine hybridization**: A steric number of 6 corresponds to \( sp^3d^2 \) hybridization.
7. **Identify bond pairs and lone pairs**: There are 4 bond pairs and \( 6 - 4 = 2 \) lone pairs.
8. **Determine molecular geometry**: The geometry is square planar, with bond angles of 90 degrees.
9. **Conclusion**: The third statement is correct; the ICl-ICl bond angle is indeed 90 degrees.

### Step 4: Analyze the fourth statement about OBr2 and OCl2
1. **Identify the central atom**: Oxygen (O).
2. **Count the valence electrons**: Oxygen has 6 valence electrons.
3. **Count the monovalent atoms attached**: There are 2 bromine (Br) atoms in OBr2 and 2 chlorine (Cl) atoms in OCl2.
4. **Analyze electronegativity**: Chlorine is more electronegative than bromine.
5. **Determine bond angles**: In OBr2, the bond angle is influenced by the lesser electronegativity of Br compared to Cl, leading to a larger bond angle in OCl2.
6. **Conclusion**: The fourth statement is incorrect; the bond angle in OBr2 is greater than in OCl2.

### Final Conclusion
The correct statements are:
1. ClF3 is T-shaped.
2. ICl4^- has a bond angle of 90 degrees.