Assertion : HDPE is a linear chain polymer
Reason : The monomer chain in HDPE are very closely packed

Options

A. If both assertion and reason are correct and reason is correct explanation for assertion
B. If both assertion and reason are correct but reason is not correct explanation for assertion
C. If assertion is correct but reason is incorrect
D. If assertion and reason are both incorrect

Explanation

To solve the question regarding the assertion and reason about HDPE (High-Density Polyethylene), we will analyze both statements step by step.

### Step 1: Understand the Assertion
**Assertion:** HDPE is a linear chain polymer.

**Explanation:**
HDPE is indeed a linear chain polymer. This means that the polymer consists of long, straight chains of repeating units (monomers). In the case of HDPE, the monomer is ethylene (CH2=CH2), and when these monomers polymerize, they form long chains without significant branching.

### Step 2: Understand the Reason
**Reason:** The monomer chains in HDPE are very closely packed.

**Explanation:**
The structure of HDPE allows the polymer chains to pack closely together due to its linear nature. This close packing is a result of the absence of branching in the polymer chains, which allows them to align and stack efficiently. This close packing contributes to the high density and strength of HDPE.

### Step 3: Evaluate the Relationship Between Assertion and Reason
Both the assertion and the reason are correct. The assertion correctly identifies HDPE as a linear chain polymer, and the reason accurately explains that the closely packed nature of the monomer chains is a characteristic of this type of polymer.

### Conclusion
Since both the assertion and reason are correct, and the reason provides a correct explanation for the assertion, the final answer is that both the assertion and reason are true, and the reason is a correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are correct, and the reason is a correct explanation of the assertion.

---