The boiling point of acetic acid is higher than expected from its molecular weight because of

Options

A. Association through hydrogen bonding
B. Strong ionizing power
C. Non-polar character
D. Solubility in water.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why the boiling point of acetic acid is higher than what would be expected based on its molecular weight.

2. **Molecular Weight Consideration**: Generally, boiling points can be predicted based on molecular weight; heavier molecules tend to have higher boiling points due to increased van der Waals forces. However, acetic acid has a relatively low molecular weight (60 g/mol) compared to other compounds with higher boiling points.

3. **Identifying the Key Factor**: The key factor that contributes to the higher boiling point of acetic acid is hydrogen bonding. Acetic acid (CH₃COOH) can form hydrogen bonds due to the presence of the hydroxyl (-OH) group.

4. **Formation of Dimers**: In the liquid state, acetic acid molecules can associate with each other to form dimers. This occurs when two acetic acid molecules interact through hydrogen bonding, creating a more complex structure.

5. **Effect of Hydrogen Bonding on Boiling Point**: The presence of hydrogen bonding increases the intermolecular forces between the acetic acid molecules. As a result, more energy (in the form of heat) is required to break these intermolecular forces to convert the liquid into vapor.

6. **Conclusion**: Therefore, the boiling point of acetic acid is higher than expected due to the strong hydrogen bonding that leads to the formation of dimers, increasing the overall intermolecular attractions.

**Final Answer**: The boiling point of acetic acid is higher than expected from its molecular weight because of hydrogen bonding, which leads to the formation of dimers and increases intermolecular forces.

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