Which of the following is not true about high density polythene?

Options

A. Tough
B. Hard
C. Inert
D. Highly branched

Explanation

To determine which statement is not true about high-density polyethylene (HDPE), we need to analyze the properties and characteristics of HDPE.

### Step-by-Step Solution:

1. **Understanding Polythene**:
- Polythene, or polyethylene, is a polymer made from the polymerization of ethylene (C2H4) monomers.
- The polymerization process is an addition reaction where unsaturated monomers react to form a saturated polymer.

**Hint**: Remember that polythene is formed from the polymerization of ethylene, which is a key characteristic.

2. **Structure of HDPE**:
- High-density polyethylene has a linear structure with minimal branching. This linearity contributes to its density and strength.
- It is important to note that the term "high density" refers to the packing of the polymer chains.

**Hint**: Focus on the structure of HDPE; it is linear and not branched.

3. **Properties of HDPE**:
- HDPE has a high melting point, typically ranging from 120 to 140 degrees Celsius.
- It is chemically inert, meaning it does not react easily with acids, bases, or alcohols.
- HDPE exhibits high tensile strength compared to other forms of polyethylene.
- It has excellent electrical insulation properties and absorbs very little water.

**Hint**: List the properties of HDPE; they include high melting point, chemical inertness, high tensile strength, and low water absorption.

4. **Identifying the Incorrect Statement**:
- Given the properties discussed, any statement claiming that HDPE is highly branched or lacks chemical inertness would be incorrect.
- The key point to remember is that HDPE is characterized by its linear structure, which is the opposite of being highly branched.

**Hint**: Look for statements that contradict the properties of HDPE, especially regarding its structure and chemical behavior.

### Conclusion:
The statement that is not true about high-density polyethylene (HDPE) is that it is highly branched. HDPE is known for its linear structure, which contributes to its high density and strength.