A milk factory produces packets of milk every day. Which of these plastics must be used in this factory for packing purposes?

Options

A. Bakelite
B. Polystyrene
C. Polythene
D. Teflon

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which type of plastic is suitable for packing milk in a factory. We need to identify the appropriate plastic that is safe and effective for this purpose.

2. **Identifying Common Plastics Used for Food Packaging**: In food packaging, especially for liquids like milk, certain types of plastics are commonly used. These include polyethylene (often referred to as polythene), polypropylene, and others.

3. **Choosing the Right Plastic**: Among the common plastics, polyethylene is widely used for milk packaging. It is safe for food contact, flexible, and has good barrier properties that help in preserving the freshness of milk.

4. **Understanding Polyethylene**: Polyethylene is made from the polymerization of ethylene (C2H4) molecules. The process involves linking these small molecules together to form long chains, which results in the plastic known as polyethylene.

5. **Conclusion**: Based on the properties and common usage, the plastic that must be used in the milk factory for packing purposes is **polythene (polyethylene)**.

**Final Answer**: Polythene (polyethylene) is the plastic used for packing milk in the factory.

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