Select the correct statements here `H_3N:+BF_3rarrH_3NrarrBF_3`

Options

A. Here `NH_3` is Lewis base while `BF_3` is Lewis acid
B. Hybridisation of `BF_3` becomes `sp^3`
C. Shape of `BF_3` remains trigonal
D. Both A and B

Answer

To analyze the reaction between ammonia (NH₃) and boron trifluoride (BF₃), we can break down the process step by step:

### Step 1: Understand the Reactants
- **Ammonia (NH₃)**: Ammonia has a nitrogen atom bonded to three hydrogen atoms and has one lone pair of electrons on the nitrogen atom.
- **Boron Trifluoride (BF₃)**: Boron trifluoride has a boron atom bonded to three fluorine atoms and has an incomplete octet, as boron only has six electrons in its valence shell.

**Hint**: Identify the electron configuration and bonding characteristics of both reactants.

### Step 2: Identify the Type of Reaction
- The reaction between NH₃ and BF₃ involves the formation of a coordinate bond. In this bond, NH₃ donates its lone pair of electrons to BF₃, which accepts the electrons to complete its octet.

**Hint**: Recognize that the formation of a coordinate bond involves one species donating a pair of electrons while the other accepts it.

### Step 3: Define Lewis Acids and Bases
- **Lewis Acid**: A substance that accepts an electron pair (BF₃ in this case).
- **Lewis Base**: A substance that donates an electron pair (NH₃ in this case).

**Hint**: Remember that a Lewis acid-base reaction involves electron pair donation and acceptance.

### Step 4: Analyze the Hybridization
- Initially, BF₃ has a trigonal planar geometry with sp² hybridization. When it forms a coordinate bond with NH₃, it can change to a tetrahedral geometry, which corresponds to sp³ hybridization.

**Hint**: Consider how the formation of new bonds can affect the hybridization of the atoms involved.

### Step 5: Evaluate the Statements
1. **Statement A**: NH₃ is a Lewis base and BF₃ is a Lewis acid. **(Correct)**
2. **Statement B**: After the bond formation, BF₃ changes from sp² to sp³ hybridization. **(Correct)**
3. **Statement C**: The formation of a new bond occurs. **(Correct)**
4. **Statement D**: BF₃ remains trigonal planar after the bond formation. **(Incorrect)**

**Hint**: Assess each statement based on the definitions of Lewis acids and bases, and the changes in hybridization.

### Conclusion
The correct statements regarding the reaction between NH₃ and BF₃ are A, B, and C. Statement D is incorrect because BF₃ does not remain trigonal planar after forming a bond with NH₃; it adopts a tetrahedral geometry.

### Final Answer
The correct statements are A, B, and C.