The hybridisation and molecular geometry of `BrF_3` molecules are :

Options

A. `sp^3d` and T shaped
B. `sp^2d^2` and tetragonal
C. `sp^3d` and bent
D. none of these

Answer

To determine the hybridization and molecular geometry of the `BrF_3` molecule, we can follow these steps:

### Step 1: Determine the Valence Electrons
- Bromine (Br) has 7 valence electrons.
- Each Fluorine (F) has 7 valence electrons, and since there are 3 fluorine atoms, they contribute a total of \(3 \times 7 = 21\) valence electrons.
- Total valence electrons in `BrF_3` = \(7 + 3 \times 7 = 7 + 21 = 28\) electrons.

### Step 2: Identify Bonding and Lone Pairs
- Bromine will form 3 bonds with the 3 fluorine atoms, using 3 of its valence electrons.
- This leaves Bromine with \(7 - 3 = 4\) valence electrons.
- These 4 remaining electrons will form 2 lone pairs (since each lone pair consists of 2 electrons).

### Step 3: Calculate the Steric Number
- The steric number is calculated as the sum of the number of bonded atoms and lone pairs.
- In `BrF_3`, there are 3 bonded fluorine atoms and 2 lone pairs on bromine.
- Steric number = \(3 \text{ (bonded atoms)} + 2 \text{ (lone pairs)} = 5\).

### Step 4: Determine Hybridization
- A steric number of 5 corresponds to \(sp^3d\) hybridization.

### Step 5: Determine Molecular Geometry
- The molecular geometry is influenced by the presence of lone pairs.
- With 2 lone pairs and 3 bonded atoms, the molecular shape is T-shaped.
- The lone pairs occupy the equatorial positions in a trigonal bipyramidal arrangement, minimizing repulsion.

### Summary
- **Hybridization**: \(sp^3d\)
- **Molecular Geometry**: T-shaped