Which one of the following statements about diborane is NOT true

Options

A. the B atoms in it are `sp^(3)` hybridised
B. It contains two 3-centre-2-electron bonds
C. All B-H bonds lengths in it are equal due to resonance
D. The molecule is non-planar

Answer

To determine which statement about diborane (B2H6) is NOT true, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Diborane**:
- Diborane (B2H6) consists of two boron atoms and six hydrogen atoms.
- Each boron atom has the electron configuration of 1s² 2s² 2p¹, which means it has three valence electrons.

2. **Hybridization of Boron in Diborane**:
- In diborane, boron undergoes sp³ hybridization.
- Each boron atom forms four bonds: two with hydrogen atoms and two as part of three-centered two-electron bonds (banana bonds) with the other boron and hydrogen atoms.

3. **Analyzing the Statements**:
- **Statement 1**: "The boron atom in its sp³ hybridized state."
- This statement is true because boron in diborane is indeed sp³ hybridized.

- **Statement 2**: "It contains 2 central or 2 electron bonds."
- This statement is true because diborane has two three-centered bonds involving the two boron atoms and the hydrogen atoms.

- **Statement 3**: "All the boron-hydrogen bond lengths are equal due to resonance."
- This statement is NOT true. In diborane, there are two types of bonds: normal covalent bonds and three-centered bonds. The bond lengths are not equal due to the different nature of these bonds.

- **Statement 4**: "The molecule is non-planar."
- This statement is true. The structure of diborane is non-planar because the arrangement of atoms does not lie in a single plane.

4. **Conclusion**:
- The statement that is NOT true about diborane is **Statement 3**: "All the boron-hydrogen bond lengths are equal due to resonance."

### Final Answer:
**The statement that is NOT true about diborane is: "All the boron-hydrogen bond lengths are equal due to resonance."**

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