In which of the following there is intermolecular hydrogen bonding ?

Options

A. Water
B. Ethanol
C. Acetic acid
D. H-F

Answer

To determine which of the given compounds exhibits intermolecular hydrogen bonding, we need to understand what intermolecular hydrogen bonding is and identify the presence of hydrogen atoms bonded to highly electronegative atoms (such as nitrogen, oxygen, or fluorine) in the compounds provided.

### Step-by-Step Solution:

1. **Understanding Intermolecular Hydrogen Bonding**:
- Intermolecular hydrogen bonding occurs between different molecules. It involves a hydrogen atom that is covalently bonded to a highly electronegative atom (like N, O, or F) and is attracted to another electronegative atom in a neighboring molecule.

2. **Analyzing Each Compound**:
- **Water (H2O)**:
- Each water molecule has two hydrogen atoms bonded to one oxygen atom. The oxygen atom can form hydrogen bonds with the hydrogen atoms of neighboring water molecules.
- **Conclusion**: Water exhibits intermolecular hydrogen bonding.

- **Ethanol (C2H5OH)**:
- Ethanol has an -OH (hydroxyl) group. The hydrogen in the hydroxyl group can form hydrogen bonds with the oxygen of another ethanol molecule.
- **Conclusion**: Ethanol exhibits intermolecular hydrogen bonding.

- **Acetic Acid (CH3COOH)**:
- Acetic acid contains a hydroxyl group (-OH) and can form hydrogen bonds between the hydrogen of one acetic acid molecule and the oxygen of another.
- **Conclusion**: Acetic acid exhibits intermolecular hydrogen bonding.

- **Hydrogen Fluoride (HF)**:
- HF has a hydrogen atom bonded to fluorine, which is highly electronegative. HF molecules can form hydrogen bonds with each other.
- **Conclusion**: Hydrogen fluoride exhibits intermolecular hydrogen bonding.

3. **Final Conclusion**:
- All the compounds listed (water, ethanol, acetic acid, and hydrogen fluoride) exhibit intermolecular hydrogen bonding.

### Summary of Findings:
- **Water (H2O)**: Yes, intermolecular hydrogen bonding.
- **Ethanol (C2H5OH)**: Yes, intermolecular hydrogen bonding.
- **Acetic Acid (CH3COOH)**: Yes, intermolecular hydrogen bonding.
- **Hydrogen Fluoride (HF)**: Yes, intermolecular hydrogen bonding.