Incorrect statement regarding `BF_(3)NH_(3)` molecule is :

Options

A. FBF bond angle `lt120^(@)`
B. HNH bond angle `gt109^(@)28'`
C. Exhibits intermolecular H-bond
D. hybridization of N-atom is `sp^(3)`

Explanation

To determine the incorrect statement regarding the molecule \( BF_3NH_3 \), we need to analyze the structure and properties of both \( BF_3 \) and \( NH_3 \) and their interaction in the complex.

### Step-by-Step Solution:

1. **Identify the Structure of \( BF_3NH_3 \)**:
- \( BF_3 \) consists of one boron atom bonded to three fluorine atoms. Boron is an electron-deficient atom (hypovalent) and has only six electrons in its valence shell.
- \( NH_3 \) consists of one nitrogen atom bonded to three hydrogen atoms, with one lone pair on the nitrogen.

2. **Hybridization and Geometry**:
- For \( BF_3 \):
- Hybridization: \( sp^2 \)
- Geometry: Trigonal planar
- Bond angle: Approximately \( 120^\circ \)
- For \( NH_3 \):
- Hybridization: \( sp^3 \)
- Geometry: Tetrahedral
- Bond angle: Approximately \( 107^\circ \)

3. **Lewis Acid-Base Interaction**:
- \( NH_3 \) acts as a Lewis base because it donates its lone pair of electrons to \( BF_3 \), which acts as a Lewis acid.
- Upon donation of the lone pair from \( NH_3 \) to \( BF_3 \), the resulting complex \( BF_3NH_3 \) will have altered bond angles due to the new electron pair interactions.

4. **Evaluating the Statements**:
- **Statement 1**: The \( F-B-F \) bond angle is less than \( 120^\circ \).
- This is correct because the presence of \( NH_3 \) can distort the bond angles.
- **Statement 2**: The \( H-N-H \) bond angle is greater than \( 109^\circ \).
- This is also correct; the donation of the lone pair can lead to a slight increase in the bond angle.
- **Statement 3**: Exhibits intermolecular hydrogen bonds.
- This is correct; \( NH_3 \) can form hydrogen bonds with other \( NH_3 \) molecules or with other polar molecules.
- **Statement 4**: The hybridization of nitrogen atoms is \( sp^3 \).
- This is correct; nitrogen in \( NH_3 \) is \( sp^3 \) hybridized.

5. **Conclusion**:
- After evaluating all statements, it appears that all provided statements are correct. Hence, there is no incorrect statement regarding \( BF_3NH_3 \).