What is the predominant intermolecular force of attraction between the adjacent chains of polymer molecules in natural rubber?

Options

A. H- bonds
B. dipole-dipole attraction
C. van der Waal's force
D. Ionic attraction

Answer

To determine the predominant intermolecular force of attraction between the adjacent chains of polymer molecules in natural rubber, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Composition of Natural Rubber**:
- Natural rubber is primarily composed of isoprene units, which are hydrocarbons. The structure of isoprene is given by the formula C5H8.

2. **Understand the Types of Intermolecular Forces**:
- The common types of intermolecular forces include:
- Hydrogen bonds
- Dipole-dipole interactions
- Van der Waals forces
- Ionic interactions

3. **Analyze the Structure of Isoprene**:
- Isoprene, being a hydrocarbon, does not have polar functional groups that would lead to hydrogen bonding or significant dipole-dipole interactions.

4. **Determine the Relevant Intermolecular Forces**:
- In hydrocarbons like isoprene, the predominant intermolecular forces are Van der Waals forces (also known as London dispersion forces). These forces arise due to temporary dipoles that occur when electron distributions around molecules fluctuate.

5. **Conclude the Predominant Intermolecular Force**:
- Since natural rubber is a polymer made from isoprene, the predominant intermolecular force between the adjacent chains of polymer molecules in natural rubber is Van der Waals forces.

### Final Answer:
The predominant intermolecular force of attraction between the adjacent chains of polymer molecules in natural rubber is **Van der Waals forces** (Option 3).

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