Which statement is true for the following reaction ?
`BF_(3)+NH_(3)rarr F_(3)B.NH_(3)`

Options

A. Hybridization of boton changes from `sp^(3)` to `sp^(2)`
B. Hybridization of nitrogen changes from `sp^(2) to sp^(3)`
C. Hybridization of boron changes from `sp^(2) to sp^(3)`
D. Hybridization of nitrogen changes from `sp^(3) to sp^(2)`

Explanation

To determine which statement is true for the reaction \( BF_3 + NH_3 \rightarrow F_3B \cdot NH_3 \), we need to analyze the hybridization of the involved species before and after the reaction.

### Step-by-Step Solution:

1. **Identify the Hybridization of \( BF_3 \)**:
- Boron in \( BF_3 \) is surrounded by three fluorine atoms and has no lone pairs.
- The hybridization of boron in \( BF_3 \) is \( sp^2 \) because it forms three sigma bonds and has a trigonal planar geometry.

2. **Identify the Hybridization of \( NH_3 \)**:
- Nitrogen in \( NH_3 \) is bonded to three hydrogen atoms and has one lone pair.
- The hybridization of nitrogen in \( NH_3 \) is \( sp^3 \) because it forms three sigma bonds and has a tetrahedral geometry.

3. **Analyze the Reaction**:
- When \( BF_3 \) reacts with \( NH_3 \), \( NH_3 \) donates its lone pair to boron, forming a coordinate bond.
- The resulting complex \( F_3B \cdot NH_3 \) has the boron atom now surrounded by four groups (three fluorine atoms and one \( NH_3 \) molecule).

4. **Determine the New Hybridization of Boron**:
- After the reaction, boron in \( F_3B \cdot NH_3 \) now has four substituents (three fluorines and one nitrogen).
- Therefore, the hybridization of boron changes from \( sp^2 \) to \( sp^3 \) to accommodate the four groups, resulting in a tetrahedral geometry.

5. **Check for Changes in Hybridization of \( NH_3 \)**:
- The hybridization of \( NH_3 \) remains \( sp^3 \) as it still has three hydrogen atoms and one lone pair.

6. **Conclusion**:
- The correct statement is that the hybridization of boron changes from \( sp^2 \) to \( sp^3 \) during the reaction.

### Final Answer:
The correct statement is: "The hybridization of boron changes from \( sp^2 \) to \( sp^3 \)."