Carboxylic acids dimerise due to

Options

A. high molecular weight
B. coordinate bonding
C. intermolecular hydrogen bonding
D. covalent bonding.

Explanation

**Step-by-Step Solution:**

1. **Understanding Carboxylic Acids**:
Carboxylic acids are organic compounds that contain a carboxyl group (-COOH). This functional group is responsible for the acidic properties of these compounds.

2. **Definition of Dimerization**:
Dimerization refers to the process where two molecules combine to form a larger molecule, known as a dimer. In the case of carboxylic acids, they can form dimers through specific interactions.

3. **Identifying the Nature of Carboxylic Acids**:
Carboxylic acids are polar molecules due to the presence of the electronegative oxygen atoms in the carboxyl group. This polarity allows for specific types of interactions between the molecules.

4. **Exploring Types of Bonding**:
The options given include:
- High molecular weight
- Coordinate bonding
- Intermolecular hydrogen bonding
- Covalent bonding

5. **Evaluating Each Option**:
- **High Molecular Weight**: Carboxylic acids generally have low to moderate molecular weights, so this option is not correct.
- **Coordinate Bonding**: This type of bonding involves the donation of a pair of electrons from one atom to another, which is not the primary interaction in carboxylic acid dimerization.
- **Intermolecular Hydrogen Bonding**: This is the primary reason for dimerization. Carboxylic acids can form hydrogen bonds between the hydrogen atom of one acid and the oxygen atom of another, leading to the formation of dimers.
- **Covalent Bonding**: While covalent bonds are present within the molecules, they do not explain the dimerization process.

6. **Conclusion**:
The correct explanation for the dimerization of carboxylic acids is due to intermolecular hydrogen bonding. Thus, the answer is **intermolecular hydrogen bonding**.

**Final Answer**: Carboxylic acids dimerize due to intermolecular hydrogen bonding.

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