Olympiad Test: Synthetic Fibres And Plastics - 1 - Class 8 MCQ

Which of these is a natural fibre?

Among the given options, the natural fiber is:

• Cotton: Cotton is a natural fiber that is obtained from the cotton plant. It is widely used in the textile industry for its softness, breathability, and absorbency.

The other options mentioned are not natural fibers:

• Polyester: Polyester is a synthetic fiber that is derived from petroleum. It is known for its durability and resistance to wrinkles, but it is not a natural fiber.


• Rayon: Rayon is a semi-synthetic fiber that is made from cellulose. While it is derived from natural materials, the manufacturing process involves chemical treatments, making it a semi-synthetic fiber.


• Nylon: Nylon is a synthetic fiber that is also derived from petroleum. It is known for its strength and elasticity, but it is not a natural fiber.

Therefore, the correct answer is Cotton.

Nylon
- Nylon is a synthetic polymer that is widely used in various applications.
- It was first introduced by the DuPont company in the 1930s.
- Nylon is known for its strength, durability, and resistance to abrasion and chemicals.
- It is commonly used in the production of fabrics, such as clothing, stockings, and parachutes.
- Nylon is also used in the manufacturing of various products, including carpets, ropes, fishing lines, and automotive parts.
- It is a lightweight material that offers excellent mechanical properties.
- Nylon is resistant to mold, mildew, and many chemicals, making it suitable for outdoor applications.
- It can be easily molded into different shapes and sizes, providing versatility in design and production.
- Nylon is a thermoplastic material, which means it can be melted and re-molded multiple times without significant degradation.
- It is a cost-effective material with a wide range of industrial applications.
- Nylon is classified as a polyamide, indicated by the letter "b" in the given answer options (B: Polyamide).
- Other common polyamides include Kevlar and Nomex.
- Polyamides are characterized by the presence of amide groups in their chemical structure.
- Nylon is not a protein (option A), polyester (option C), or cellulose (option D).
In conclusion, the correct answer is option B: Polyamide.

Terylene, Terene, and Dacron are different types of polyester fibers.
Polyester is a synthetic fiber that is known for its durability, wrinkle resistance, and quick-drying properties. It is widely used in the textile industry for making various types of clothing, home furnishings, and industrial materials. Terylene, Terene, and Dacron are specific brand names or trade names for polyester fibers.
Here are some key points about polyester fibers:
- Polyester fibers are made from a polymer called polyethylene terephthalate (PET), which is derived from petroleum.
- Terylene, Terene, and Dacron are all brand names for polyester fibers that were developed by different companies.
- Terylene is a brand name for polyester fibers that was developed by Imperial Chemical Industries (ICI) in the United Kingdom.
- Terene is a brand name for polyester fibers that was developed by Celanese Corporation in the United States.
- Dacron is a brand name for polyester fibers that was developed by DuPont in the United States.
- All three types of polyester fibers have similar properties and can be used for a wide range of applications, including clothing, upholstery, bedding, and industrial materials.
In conclusion, Terylene, Terene, and Dacron are all different brand names for polyester fibers. They are known for their durability, wrinkle resistance, and quick-drying properties, making them popular choices in the textile industry.

Explanation:
Chemically Derived Fibers:
- Rayon: Rayon is a semi-synthetic fiber made from cellulose, which is derived from chemicals.
- Nylon: Nylon is a synthetic fiber made from chemicals derived from petroleum.
Natural Fibers:
- Cotton: Cotton is a natural fiber derived from the cotton plant.
- Silk: Silk is a natural fiber derived from the silkworm.
Therefore, the fiber derived from chemicals is Nylon (option C).

To determine which fiber is made from wood, we need to analyze each option and identify the correct one. Let's break down the options and their characteristics:
1. Rayon:
- Rayon is a fiber made from regenerated cellulose, which can be derived from wood pulp.
- It is a semi-synthetic fiber.
- Rayon is known for its softness, breathability, and silk-like appearance.
2. Nylon:
- Nylon is a synthetic fiber made from petrochemicals.
- It is not derived from wood.
3. Terylene:
- Terylene is the brand name for polyester fiber.
- Polyester is a synthetic fiber made from petrochemicals.
- It is not derived from wood.
4. Cotton:
- Cotton is a natural fiber derived from the cotton plant.
- It is not made from wood.
Based on the analysis, we can conclude that Rayon is the fiber that is made from wood. It is important to note that while Rayon is made from wood pulp, it undergoes a chemical process to convert the pulp into a fiber form.
Therefore, the correct answer is A: Rayon.

Rayon is prepared by the Viscose process.
The Viscose process is a method used to produce rayon, a versatile synthetic fiber. It involves the following steps:
1. Cellulose Extraction:
- Cellulose is extracted from wood pulp or cotton linters.
- Wood pulp is treated with chemicals to remove impurities and break down the cellulose into a more soluble form.
2. Alkali Treatment:
- The cellulose is treated with an alkali solution, usually sodium hydroxide (NaOH), to further break it down.
- This process is known as mercerization and improves the reactivity of cellulose.
3. Xanthation:
- The treated cellulose is then soaked in a solution of sodium hydroxide and carbon disulfide (CS2).
- This converts the cellulose into a compound called sodium cellulose xanthate.
4. Viscose
- The sodium cellulose xanthate is dissolved in a dilute solution of sodium hydroxide to form a viscose solution.
- This solution has a syrup-like consistency and can be spun into fibers.
5. Filament Formation:
- The viscose solution is forced through spinnerets, which are small holes, to form fine filaments.
- The filaments are then coagulated in a bath of sulfuric acid (H2SO4) to solidify the rayon fibers.
6. Washing and Finishing:
- The solidified fibers are washed to remove any residual chemicals.
- They are then treated with chemicals to improve their strength, flexibility, and other desired properties.
- The fibers can be further processed into various forms, such as yarn or fabric.
In conclusion, rayon is prepared by the Viscose process, which involves extracting cellulose from wood pulp or cotton linters, treating it with alkali, xanthating it with sodium hydroxide and carbon disulfide, dissolving it in sodium hydroxide solution to form a viscose solution, spinning it into filaments, coagulating the filaments, washing and finishing the solidified fibers.

Polythene is a polymer used to make various products, including:
- Tyres: Polythene is used in the manufacturing of tyres due to its high strength and durability. It helps to provide resilience and stability to the tyres, enabling them to withstand the pressure and wear of daily use.
- Plastic containers: Polythene is commonly used to make plastic containers such as bottles, jars, and food packaging. It is a lightweight and flexible material that is resistant to moisture and chemicals, making it suitable for storing a wide range of products.
- Textiles: Polythene can also be used in the production of textiles. It is often blended with other fibers, such as cotton or polyester, to enhance their properties. Polythene fibers can add strength, elasticity, and water resistance to fabrics, making them suitable for applications such as outdoor clothing or waterproof materials.
- Shoes: Polythene can be found in the production of various types of shoes, including athletic shoes, sandals, and flip-flops. It is used to create the outsole or the midsole of the shoes, providing cushioning, shock absorption, and durability.
In conclusion, polythene is a versatile polymer that is used in the manufacturing of products such as tyres, plastic containers, textiles, and shoes. Its properties make it an ideal material for applications that require strength, flexibility, and resistance to moisture and chemicals.

Nylon is used in making of:
- Conveyor belts: Nylon is widely used in the manufacturing of conveyor belts due to its high strength, durability, and resistance to abrasion. It provides excellent grip and ensures smooth movement of goods.
- Fishing nets: Nylon is a popular choice for making fishing nets due to its strength and ability to withstand harsh conditions. It is lightweight, resistant to water absorption, and has good elasticity, making it ideal for catching fish.
- Combs: Nylon combs are commonly used because of their smooth and flexible teeth. They are gentle on the scalp, reduce static, and are resistant to breakage. Nylon combs are also easy to clean and maintain.

1. Monomers:

   • Monomers are the basic building blocks of polymers. They are small molecules that chemically bond together to form polymers. Monomers themselves are not fibers, but they are used to create polymers which are then used to make synthetic fibers.

2. Plastic fibres:

   • While plastic fibers are a type of synthetic fiber, the term "plastic fibres" is not commonly used in the general sense. Synthetic fibers encompass a broader range of materials, including those made from various polymers, not just plastics.

3. Artificial fibres:

   • This term is sometimes used interchangeably with "synthetic fibres," but it is less specific. "Artificial fibres" generally refer to fibers made from man-made processes, including both synthetic fibers and some regenerated fibers (e.g., rayon). "Synthetic fibres" is the more precise term for fibers made from polymers.

In summary, the most accurate and commonly used term for human-made fibers derived from polymers is:

2. Synthetic fibres

To identify the thermosetting plastic among the given options, we need to understand the characteristics of thermosetting plastics. Thermosetting plastics are a type of polymer that undergoes a chemical reaction during molding and hardens irreversibly. They cannot be melted or reshaped once they have been set.
Among the options provided, the thermosetting plastic is:
Bakelite (Option C)
Explanation:
- Bakelite is a thermosetting plastic that was one of the first synthetic plastics invented.
- It is formed by the condensation polymerization of phenol and formaldehyde.
- Once it is molded and hardened, it cannot be softened or reshaped by heat.
- Bakelite is known for its high heat resistance, electrical insulation properties, and durability.
- It is commonly used in electrical switches, handles, and various industrial applications.
Other options:
- Polystyrene (Option A) is a thermoplastic, which means it can be melted and reshaped multiple times.
- Polythene (Option B) is also a thermoplastic commonly known as polyethylene.
- PVC (Option D) is a thermoplastic polymer that can be softened and reshaped by heat.
Therefore, the correct answer is C: Bakelite