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 options exhibits intermolecular hydrogen bonding, we will analyze each compound based on the presence of hydrogen atoms bonded to highly electronegative atoms (like nitrogen, oxygen, or fluorine) and the ability of these compounds to interact with other molecules.

### Step-by-Step Solution:

1. **Understanding Hydrogen Bonding**:
- Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative atom (N, O, or F) and interacts with another electronegative atom in a different molecule.
- There are two types of hydrogen bonding: intramolecular (within the same molecule) and intermolecular (between different molecules).

2. **Analyzing Water (H₂O)**:
- Water consists of two hydrogen atoms bonded to one oxygen atom.
- The oxygen atom is highly electronegative, and the hydrogen atoms can form hydrogen bonds with the oxygen of other water molecules.
- **Conclusion**: Water exhibits intermolecular hydrogen bonding.

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

4. **Analyzing Acetic Acid (CH₃COOH)**:
- Acetic acid contains a carboxyl group (-COOH) where the hydrogen is attached to the highly electronegative oxygen.
- This hydrogen can form hydrogen bonds with the oxygen of other acetic acid molecules.
- **Conclusion**: Acetic acid exhibits intermolecular hydrogen bonding.

5. **Analyzing Hydrofluoric Acid (HF)**:
- HF consists of hydrogen bonded to fluorine, which is highly electronegative.
- The hydrogen atom can interact with the fluorine of another HF molecule, leading to hydrogen bonding.
- **Conclusion**: HF exhibits intermolecular hydrogen bonding.

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

### Final Answer:
All options (A: Water, B: Ethanol, C: Acetic Acid, D: Hydrofluoric Acid) exhibit intermolecular hydrogen bonding.

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