Which is/are true in case of `BF_(3)` ?

Options

A. It is volatile liquid even at room temperature
B. It is Lewis acid
C. It has planer geometry
D. It forms adduct with `NH_(3)`

Answer

To determine which statements are true regarding BF₃ (Boron Trifluoride), we will analyze each option provided.

### Step-by-Step Solution:

1. **Evaluate the first statement: "BF₃ is a volatile liquid at room temperature."**
- BF₃ has a low melting point and is actually a gas at room temperature. Therefore, this statement is **false**.

2. **Evaluate the second statement: "BF₃ is a Lewis acid."**
- BF₃ has only six electrons in its valence shell (it has three bonds with fluorine and no lone pairs). This makes it electron-deficient and capable of accepting an electron pair, which qualifies it as a Lewis acid. Therefore, this statement is **true**.

3. **Evaluate the third statement: "BF₃ has a planar geometry."**
- The molecular geometry of BF₃ is trigonal planar due to the three fluorine atoms surrounding the boron atom, which is in the center. Thus, this statement is also **true**.

4. **Evaluate the fourth statement: "BF₃ forms adducts with NH₃."**
- BF₃, being a Lewis acid, can react with NH₃, which is a Lewis base, to form an adduct. This reaction occurs as NH₃ donates an electron pair to the electron-deficient boron atom in BF₃. Therefore, this statement is **true**.

### Conclusion:
The true statements regarding BF₃ are:
- **B (BF₃ is a Lewis acid)**
- **C (BF₃ has a planar geometry)**
- **D (BF₃ forms adducts with NH₃)**

### Final Answer:
The correct options are B, C, and D.

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