Which of the following molecules are expected to exhibit intermolecular H-bonding ?
(I) Acetic acid ((II) o-nitrophenol (III) m-nitrophenol (IV)o-boric acid
Select correct alternate :

Options

A. I, II, III
B. I,II,IV
C. I,III,IV
D. II,III,IV

Answer

To determine which of the given molecules exhibit intermolecular hydrogen bonding, we need to analyze each molecule for the presence of hydrogen bonding capabilities. Hydrogen bonding typically occurs when a hydrogen atom is bonded to a highly electronegative atom (such as N, O, or F) and can interact with another electronegative atom in a different molecule.

### Step-by-Step Solution:

1. **Acetic Acid (CH₃COOH)**:
- Acetic acid has a hydroxyl (-OH) group that can form hydrogen bonds.
- The hydrogen atom of the -OH group can form a hydrogen bond with the oxygen atom of another acetic acid molecule.
- **Conclusion**: Acetic acid exhibits intermolecular hydrogen bonding.

2. **Ortho-Nitrophenol (o-Nitrophenol)**:
- Ortho-nitrophenol has both a hydroxyl (-OH) group and a nitro (-NO₂) group.
- The -OH group can form hydrogen bonds with the oxygen of another -OH group in a different molecule.
- **Conclusion**: Ortho-nitrophenol exhibits intermolecular hydrogen bonding.

3. **Meta-Nitrophenol (m-Nitrophenol)**:
- Meta-nitrophenol also has a hydroxyl (-OH) group that can form hydrogen bonds.
- The -OH group can interact with the oxygen of another -OH group in a different molecule.
- **Conclusion**: Meta-nitrophenol exhibits intermolecular hydrogen bonding.

4. **Ortho-Boric Acid (o-Boric Acid)**:
- Boric acid (H₃BO₃) can form hydrogen bonds due to the presence of hydroxyl groups.
- The -OH groups can interact with the oxygen of another boric acid molecule.
- **Conclusion**: Ortho-boric acid exhibits intermolecular hydrogen bonding.

### Final Answer:
The molecules that exhibit intermolecular hydrogen bonding are:
- (I) Acetic Acid
- (II) Ortho-Nitrophenol
- (III) Meta-Nitrophenol
- (IV) Ortho-Boric Acid