Select correct statements:

Options

A. `B_(2)H_(6)` is stronger lewis acid than `BF_(3)`
B. `BF_(3)` is weaker lewis acid than `BCl_(3)`
C. `B_(2)H_(6)` is not a lewis acid
D. In `B_(2)H_(6)` all `'H'` atoms are not in the same plane

Answer

To solve the question of selecting the correct statements regarding the Lewis acids and structures of boron compounds, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Evaluate Statement 1: "B2H6 is a stronger Lewis acid than BF3."**
- **Analysis**: BF3 is known to be a stronger Lewis acid compared to B2H6. BF3 has a higher electron deficiency due to the electronegativity of fluorine, which pulls electron density away from boron. Therefore, this statement is **incorrect**.

2. **Evaluate Statement 2: "BF3 is a weaker Lewis acid than BCl3."**
- **Analysis**: BF3 has effective backbonding due to the smaller size of fluorine, which allows for better overlap of orbitals. In contrast, BCl3 does not have effective backbonding because chlorine's larger 3p orbitals do not overlap well with boron's 2p orbitals. Thus, BCl3 is indeed a stronger Lewis acid than BF3. This statement is **correct**.

3. **Evaluate Statement 3: "B2H6 is not a Lewis acid."**
- **Analysis**: B2H6 (Diborane) is indeed a Lewis acid because it can accept electron pairs in its vacant orbitals. This statement is **incorrect**.

4. **Evaluate Statement 4: "In B2H6, all hydrogen atoms are not in the same plane."**
- **Analysis**: The structure of B2H6 is such that it has bridging hydrogen atoms that are positioned above and below the plane of the boron atoms. Therefore, this statement is **correct**.

### Conclusion:
The correct statements are:
- Statement 2: "BF3 is a weaker Lewis acid than BCl3."
- Statement 4: "In B2H6, all hydrogen atoms are not in the same plane."

### Final Answer:
The correct statements are **2 and 4**.