Assertion : The correct order of increasing molecular forces in the given polymres is : Buna-S, Polythene, Nylon -6,6
Reason : The properties of polymers depends upon the molecular forces.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion .
B. If both assertion and reason are true but reason is not the correct explanation of assertion .
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the assertion-reason question regarding the order of increasing molecular forces in the given polymers (Buna-S, Polythene, Nylon-6,6), we will analyze each polymer based on their intermolecular forces and properties.

### Step-by-Step Solution:

1. **Identify the Polymers**: The polymers mentioned are:
- Buna-S (a type of synthetic rubber)
- Polythene (polyethylene, a common thermoplastic)
- Nylon-6,6 (a synthetic fiber)

2. **Analyze Buna-S**:
- Buna-S is an elastomer, which means it is flexible and has rubber-like properties.
- The intermolecular forces in elastomers are primarily van der Waals forces, which are relatively weak compared to other types of intermolecular forces.

3. **Analyze Polythene**:
- Polythene is a thermoplastic polymer.
- The intermolecular forces in polythene are stronger than those in Buna-S but are still considered intermediate in strength. These forces include van der Waals forces and some degree of dipole-dipole interactions.

4. **Analyze Nylon-6,6**:
- Nylon-6,6 is a synthetic fiber known for its strength and durability.
- It has strong intermolecular forces due to hydrogen bonding between the amide groups in the polymer chain, making it the strongest among the three polymers.

5. **Order of Increasing Molecular Forces**:
- Based on the analysis:
- Buna-S has the weakest intermolecular forces.
- Polythene has intermediate intermolecular forces.
- Nylon-6,6 has the strongest intermolecular forces.
- Therefore, the correct order of increasing molecular forces is: **Buna-S < Polythene < Nylon-6,6**.

6. **Assertion and Reason Evaluation**:
- **Assertion**: The statement about the order of increasing molecular forces is correct.
- **Reason**: The properties of polymers depend on molecular forces, which is also true.
- However, the reason does not specifically explain the assertion, as it is a general statement about polymers.

### Conclusion:
Both the assertion and reason are true, but the reason is not the correct explanation for the assertion. Thus, the answer is that both statements are true, but the reason does not support the assertion directly.

### Final Answer:
**Option B**: Both assertion and reason are true, but reason is not the correct explanation for the assertion.

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