In diborane

Options

A. Four bridged hydrogen atoms and two terminal hydrogen atoms are present
B. Two bridged hydrogen atoms and four terminal hydrogen atoms are present
C. three bridged hydrogen atoms and three terminal hydrogen atoms are present
D. there are no bridged hydrogen atoms in diborane, only hydrogen bonds are present.

Answer

**Step-by-Step Solution:**

1. **Understanding Diborane Structure**: Diborane (B2H6) consists of two boron atoms and six hydrogen atoms. The structure is crucial for identifying the types of hydrogen atoms present (terminal and bridge).

2. **Hybridization of Boron**: Boron has an atomic number of 5 and an electronic configuration of 1s² 2s² 2p¹. In diborane, one of the 2s electrons is promoted to the 2p orbital, leading to an excited state configuration of 1s² 2s¹ 2p². This results in sp³ hybridization of the boron atoms.

3. **Drawing the Structure**: In diborane, each boron atom uses its sp³ hybrid orbitals to form bonds. Two of the hydrogen atoms bond to each boron atom in terminal positions, while the remaining two hydrogen atoms form bridge bonds between the two boron atoms.

4. **Identifying Hydrogen Types**: In the diborane structure:
- There are **4 terminal hydrogen atoms** (two attached to each boron).
- There are **2 bridge hydrogen atoms** (which connect the two boron atoms).

5. **Analyzing the Options**:
- Option A states there are 2 bridge hydrogen atoms - **Correct**.
- Option B states there are 2 bridge hydrogen atoms and 4 terminal hydrogen atoms - **Correct**.
- Option C states there are 3 bridge hydrogen atoms - **Incorrect**.
- Option D states there are no bridge hydrogen atoms - **Incorrect**.

6. **Conclusion**: The correct answer is Option B, which states there are 2 bridge hydrogen atoms and 4 terminal hydrogen atoms.

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