Which of the following molecule has trigonal planner geometry?

Options

A. `IF_(3)`
B. `PCl_(3)`
C. `NH_(3)`
D. `BF_(3)`

Answer

To determine which of the given molecules has a trigonal planar geometry, we need to analyze the hybridization and steric number of each molecule. Trigonal planar geometry corresponds to sp² hybridization, which occurs when there are three sigma bonds and no lone pairs around the central atom.

### Step-by-Step Solution:

1. **Identify the Molecules:**
We need to examine the given options. Let's assume the options are ICl₃, PCl₃, NH₃, and BF₃.

2. **Analyze ICl₃ (Iodine Trichloride):**
- Iodine has 7 valence electrons.
- It forms 3 bonds with chlorine atoms.
- Remaining valence electrons: 7 - 3 = 4 (which are 2 lone pairs).
- **Steric Number:** 3 (bond pairs) + 2 (lone pairs) = 5.
- **Hybridization:** sp³ (not trigonal planar).

3. **Analyze PCl₃ (Phosphorus Trichloride):**
- Phosphorus has 5 valence electrons.
- It forms 3 bonds with chlorine atoms.
- Remaining valence electrons: 5 - 3 = 2 (which is 1 lone pair).
- **Steric Number:** 3 (bond pairs) + 1 (lone pair) = 4.
- **Hybridization:** sp³ (not trigonal planar).

4. **Analyze NH₃ (Ammonia):**
- Nitrogen has 5 valence electrons.
- It forms 3 bonds with hydrogen atoms.
- Remaining valence electrons: 5 - 3 = 2 (which is 1 lone pair).
- **Steric Number:** 3 (bond pairs) + 1 (lone pair) = 4.
- **Hybridization:** sp³ (not trigonal planar).

5. **Analyze BF₃ (Boron Trifluoride):**
- Boron has 3 valence electrons.
- It forms 3 bonds with fluorine atoms.
- Remaining valence electrons: 3 - 3 = 0 (no lone pairs).
- **Steric Number:** 3 (bond pairs) + 0 (lone pairs) = 3.
- **Hybridization:** sp² (trigonal planar).

6. **Conclusion:**
The molecule with trigonal planar geometry is **BF₃**.

### Final Answer:
The molecule that has trigonal planar geometry is **BF₃**.