Which of the following is the strongest synthetic fibre? 

Nylon 

The correct answer is option 1. Nylon.

Nylon is a synthetic polymer and is considered one of the strongest synthetic fibers. Its strength is attributed to its molecular structure, which consists of long chains of repeating units linked by amide groups. This structure gives nylon several properties that contribute to its strength:

1. High Tensile Strength:  Nylon fibers have a high tensile strength, meaning they can withstand a significant amount of pulling or stretching force without breaking. This property makes nylon suitable for applications where strength and resilience are essential, such as in ropes, fishing lines, and other load-bearing materials.

2. Durability:  Nylon is known for its durability and resistance to abrasion. It can withstand wear and tear, making it suitable for applications that involve constant friction or rubbing.

3. Flexibility: Nylon fibers are flexible and can bend without breaking. This flexibility enhances their performance in various applications, such as in textiles and other materials that require a degree of elasticity.

4. Chemical Resistance: Nylon is resistant to many chemicals, which adds to its overall durability and suitability for different environments.

Due to these properties, nylon is commonly used in a wide range of products, including clothing, carpets, tire cords, industrial ropes, and more. Its strength and versatility have made it a popular choice in various industries where durable and high-performance materials are required.