**Correct Option: C. Polyethylene terephthalate (PET)** ### Detailed Explanation: **1. Understanding the Properties of PET:** Polyethylene terephthalate (PET) is a type of polyester that is widely used in the production of plastic bottles and containers. The reasons for its popularity include: - **Strength:** PET has excellent tensile strength, which means it can withstand significant stress without breaking. This is crucial for containers that need to hold liquids under pressure. - **Lightweight:** PET is lighter than many other materials, making it easier to transport and handle. This is particularly important for consumer products like beverage bottles. - **Chemical Resistance:** PET is resistant to many chemicals, which helps preserve the contents of the bottles and containers without leaching harmful substances. - **Transparency:** PET can be made clear, allowing consumers to see the contents of the bottle, which is a desirable feature for many products. **2. Why Other Options Are Incorrect:** - **A. Polyvinyl chloride (PVC):** - **Properties:** PVC is a versatile plastic used in construction, plumbing, and electrical applications. While it is strong and durable, it is not typically used for food and beverage containers due to concerns about leaching harmful chemicals (like phthalates) into food and drink. - **Conclusion:** PVC is not commonly used for plastic bottles and containers intended for consumer use. - **B. Polystyrene (PS):** - **Properties:** Polystyrene is often used for disposable cutlery, plates, and foam packaging. It is not as strong or durable as PET and can be brittle, making it unsuitable for containers that need to hold liquids under pressure. - **Conclusion:** Polystyrene is not a suitable choice for plastic bottles and containers. - **D. Polypropylene (PP):** - **Properties:** Polypropylene is used in a variety of applications, including food containers and automotive parts. While it has good chemical resistance and is lightweight, it does not have the same level of clarity and strength as PET for beverage containers. - **Conclusion:** Although polypropylene is used for some containers, PET is preferred for beverage bottles due to its superior properties. ### Summary of Key Points: - **PET (Polyethylene terephthalate)** is the preferred polymer for plastic bottles and containers due to its strength, lightweight nature, chemical resistance, and transparency. - **PVC (Polyvinyl chloride)** is not commonly used for food and beverage containers due to safety concerns. - **Polystyrene (PS)** is brittle and unsuitable for liquid containers. - **Polypropylene (PP)**, while useful, does not match PET's properties for beverage applications. ### Revision Summary: - **PET is strong, lightweight, and chemically resistant, making it ideal for bottles.** - **PVC is avoided in food applications due to potential leaching.** - **Polystyrene is brittle and not suitable for liquid containers.** - **Polypropylene is useful but lacks the clarity and strength of PET for beverage use.**