In which of the following molecules is hydrogen bridge bond present ?

Options

A. Water
B. Inorganic benzene
C. Diborane
D. Methanol

Answer

To determine which of the given molecules contains a hydrogen bridge bond, we will analyze each option step by step.

### Step 1: Understand Hydrogen Bridge Bonds
A hydrogen bridge bond (or hydrogen bond) occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen or nitrogen) interacts with another electronegative atom. This bond is typically weaker than covalent bonds but plays a crucial role in the properties of substances, especially in water and organic compounds.

### Step 2: Analyze Each Option

1. **Water (H₂O)**:
- Structure: Water has a bent shape with two hydrogen atoms bonded to an oxygen atom.
- Analysis: Water molecules can form hydrogen bonds with each other due to the presence of the highly electronegative oxygen atom. However, the question is asking for a hydrogen bridge bond in the context of a single molecule, which is not applicable here.
- Conclusion: **No hydrogen bridge bond** in the context of a single molecule.

2. **Inorganic Benzene (B₃N₃H₆)**:
- Structure: Inorganic benzene has a cyclic structure with alternating boron and nitrogen atoms, with hydrogen atoms attached to the boron atoms.
- Analysis: While there are hydrogen atoms present, the structure does not allow for the formation of hydrogen bridge bonds as seen in typical hydrogen bonding scenarios.
- Conclusion: **No hydrogen bridge bond** present.

3. **Diborane (B₂H₆)**:
- Structure: Diborane consists of two boron atoms and six hydrogen atoms, with two terminal hydrogen atoms and four bridging hydrogen atoms.
- Analysis: The bridging hydrogen atoms create a unique structure where they can be considered as forming hydrogen bridge bonds between the two boron atoms.
- Conclusion: **Hydrogen bridge bonds are present** in diborane.

4. **Methanol (CH₃OH)**:
- Structure: Methanol consists of a methyl group (CH₃) attached to a hydroxyl group (OH).
- Analysis: Methanol can form hydrogen bonds with other methanol molecules due to the presence of the hydroxyl group, but again, this is not a hydrogen bridge bond in the context of a single molecule.
- Conclusion: **No hydrogen bridge bond** in the context of a single molecule.

### Final Answer
The molecule that contains a hydrogen bridge bond is **Diborane (B₂H₆)**.

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