High density polythene is obtained by

Options

A. polymerisation of ethene in a hydrocarbon solvent in the presence of Ziegler - Natta catalyst
B. polymerisation of ethene under high pressure and temperature
C. free radical polymerisation of ethene at low temperature in presence of peroxide
D. polymerisation of ethene in presence of carbon tetrachloride

Answer

**Step-by-Step Solution:**

1. **Understanding High-Density Polyethylene (HDPE)**:
- High-density polyethylene (HDPE) is a type of polymer made from the polymerization of ethylene (C2H4) monomers. It is known for its strength, durability, and resistance to impact.

2. **Polymerization Process**:
- The process of forming HDPE involves the addition polymerization of ethylene. This means that multiple ethylene molecules are chemically bonded together to form long chains, creating the polymer.

3. **Catalyst Used**:
- The polymerization of ethylene to produce HDPE is typically carried out in the presence of a catalyst known as the Ziegler-Natta catalyst. This catalyst is a combination of titanium tetrachloride (TiCl4) and an organoaluminum compound (such as triethylaluminum, C2H5) which enhances the efficiency of the polymerization process.

4. **Conditions for Polymerization**:
- The polymerization occurs in a hydrocarbon solvent and at relatively low temperatures and pressures compared to other polymerization methods. This controlled environment is crucial for producing the high-density structure of the polymer.

5. **Properties of HDPE**:
- HDPE is characterized by its high density, which makes it tougher and harder than low-density polyethylene (LDPE). It is chemically inert, meaning it does not react easily with other chemicals, making it suitable for various applications.

6. **Applications of HDPE**:
- Due to its properties, HDPE is widely used in the manufacturing of containers, bottles, and other durable goods such as buckets and piping.

**Conclusion**:
High-density polyethylene is obtained by the polymerization of ethylene in the presence of the Ziegler-Natta catalyst.

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