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Synthetic fibres or threads - class-VIII

Description: synthetic fibres or threads
Number of Questions: 36
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Tags: fibre to fabric synthetic fibres and plastics polymer chemistry substances in daily use chemistry
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Bed sheets are made up of:

  1. rayon and wool

  2. rayon and plastic

  3. rayon and nylon

  4. rayon and cotton


Correct Option: D
Explanation:

Bedsheets are made by blended fibre i.e. a mixture of rayon and cotton. Rayon is a versatile fibre and is widely claimed to have the same comfort properties as natural fibres, although the drape and slipperiness of rayon textiles are often more like nylon. It can imitate the feel and texture of silk, wool, cotton and linen. The fibres are easily dyed in a wide range of colours.

Which of the following is a disadvantage of nylon?

  1. They do not shrink

  2. They are less resistant to sun light

  3. They are resistant to insects and molds

  4. They can be easily dyed


Correct Option: B
Explanation:

Nylon fabrics have low resistance to sunlight. 


They are not suitable for curtains or draperies as it is weakened by the exposure to sunlight.

Hence the correct option is B.

The fibres of nylon is stronger than :

  1. steel wire of same thickness

  2. steel wire of different thickness

  3. plastic fibres

  4. rayon


Correct Option: A
Explanation:

Nylon is a synthetic fibre which has certain chemical properties which makes their fibres strong.

The fibre which gives smell of plastic is: 

  1. rayon

  2. silk

  3. wool

  4. nylon


Correct Option: D
Explanation:

Nylon fibre gives smell of plastic.

This is because it is very similar to plastic.
Rayon, Wool, and Silk are the natural polymers which do not have plastic like smell.

Which of the following statement is true?

  1. A nylon thread is stronger than a steel wire

  2. Rayon is a natural fibre made from wood pulp

  3. Cotton is not a polymer

  4. Fabric made from polyester can get wrinkles easily


Correct Option: A
Explanation:

A. Nylon thread is stronger than steel wire because nylon fibre is made up of strong amide linkages which gives it strength.

B. Rayon is a regenerated fibre so it is not natural.

C. Cotton is a polymer of cellulose.

D. Polyester materials are wrinkle-free.

Nylon fibre is useful, because of following properties:

  1. soft, strong and light

  2. transparent, light and easy to wash

  3. strong, elastic and light

  4. hard, inexpensive and strong


Correct Option: C
Explanation:

Nylon fibre is strong, elastic and light. It is lustrous and easy to wash.

A silk saree and a nylon saree, both of same length are put to dry under sun. Which one will dry faster?

  1. Silk saree

  2. Nylon saree

  3. Both will take same time

  4. Depends on weather condition


Correct Option: B
Explanation:

Nylon has various characteristics like a higher impact resistance, a more rapid moisture absorption, greater elasticity and elastic recovery. Nylon absorbs moisture readily as compared to silk so nylon saree dries up faster than silk saree in the sun.

Ropes made of nylon and polyester are commonly used in cranes and elevators because :

  1. Nylon is inflammable

  2. It is a good conductor of heat and electricity

  3. It is very strong, fairly elastic and light weight

  4. It is heat resistant


Correct Option: C
Explanation:

Ropes made of nylon and polyester are commonly used in cranes and elevators because It is very strong, fairly elastic and light weight.

Rayon is different from synthetic fibres because :

  1. it has a silk appearance

  2. it is obtained from wood pulp

  3. it can also be woven like those of natural fibres

  4. it is natural


Correct Option: B
Explanation:

Rayon is manufactured regenerated cellulose fiber. It is made from purified cellulose from wood pulp which is converted into soluble compound which is chemically solidified to form synthetic fiber. Because rayon is manufactured from naturally occurring polymers, it is considered a semi-synthetic fiber.

Synthetic fibres having almost common property are:

  1. nylon and polyster

  2. nylon and plastics

  3. polyster and plastics

  4. all of the above


Correct Option: A
Explanation:

Synthetic fibres having commmon property are nylon and polyster.

Which of the following statements is incorrect?

  1. Nylon clothings can with stand high temperature and are, therefore, good to wear in summers.

  2. Thermosetting plastics do not become soft on heating.

  3. Addition polymers are formed without the elimination of byproduct molecules.

  4. Natural rubber is obtained as latex from rubber trees.


Correct Option: A

Read the following statement and mark the correct answer.


I. Artificially prepared synthetic fibre which resembles silk is known as terylene.
II. Rayon is not considered as a synthetic fibre as it is regenerated from cellulose.
III. PET bottles and jars are made up of polyesters. 

  1. Statement I is false, II and III are true

  2. Statement I is true, II and III are false

  3. Statement I and II are false, III is true

  4. Statement II is true, I and II are false


Correct Option: A

The fibre developed in Newyork & London simultaneously is known as:

  1. rayon 

  2. silk

  3. PVC

  4. nylon


Correct Option: D

The fibre obtained from cellulose is:

  1. polyester

  2. nylon

  3. acrylic

  4. rayon


Correct Option: D
Explanation:

The fibre obtained from cellulose is rayon.


Because of the reconversion of the soluble compound to cellulose, rayon is referred to as a regenerated cellulose fibre. 

There are several types of rayon fibers in commercial use today, named according to the process by which the cellulose is converted to the soluble form and then regenerated.

Thus, option $D$ is correct.

Nylon is an example of thermoplastic.

  1. True

  2. False


Correct Option: A
Explanation:

 Nylon is a thermoplastic silky material that can be melt-processed into fibers.


Thermoplastics are the polymers which lose their shape on heating and regain their shape on cooling.

Examples: Nylon, PVC, polystyrene, etc.

Rayon is:

  1. natural silk.

  2. artificial silk.

  3. regenerated fibre.

  4. synthetic fibre.


Correct Option: C
Explanation:

Rayon is a regenerated fibre.


It is obtained from nature and then it is processed in factories in order to get the desired properties.
Hence, C is correct option.

_________  is stronger than steel wire.       

  1. Cotton fibre

  2. Silk thread

  3. Plastic thread

  4. Nylon fibre


Correct Option: D

The material similar to silk in appearance is :

  1. nylon

  2. rayon

  3. polyester

  4. terylene


Correct Option: B
Explanation:
The material similar to silk in appearance is rayon. 

Since rayon resembles silk in appearance, it is called artificial silk.

It is a man-made fibre obtained from a natural source wood pulp.

Hence the correct option is B.

The fibre developed in Newyork & London simultaneously is :

  1. Nylon

  2. Rayon

  3. Teflon

  4. Silk


Correct Option: A
Explanation:

Nylon got its name Ny from Newyork and Lon from London.
Option A is correct.

Which of the following do not contain polyester fabric?

  1. Terrywool

  2. Terrycot

  3. Terylene

  4. Orlon


Correct Option: D
Explanation:

Terrywool, Terrycot and Terylene all contain polyester.


Orlon is a polymer of vinyl cyanide. It is made by the addition of acrylonitrile molecules. It is a brand of the synthetic, acrylic textile fibre of the lightweight and wrinkle-resistant fabric.

Option D is correct.

Which of the following is a true statement?

  1. Plastic is soluble in water

  2. Plastic is not a polymer

  3. Rayon is made from cellulose

  4. All plastics are fire-resistant


Correct Option: C
Explanation:

Rayon is made from cellulose.

The first man - made polymer is :

  1. PVC

  2. Teflon

  3. Bakelite

  4. Nylon


Correct Option: C
Explanation:

Bakelite is a man made polymer by polymerization of phenol and formaldehyde. First Navoloc is formed and then Bakelite is formed.

Which of the following is known as regenerated fibre?

  1. Nylon - 66

  2. Terylene

  3. Nylon - 6

  4. Rayon


Correct Option: D
Explanation:

Rayon is known as regenerated fibre because it is manufactured from natural resources like cellulose present in wood pulp and short fibres.

Polyester consists of :

  1. repeating unit of ether

  2. monomer of ester

  3. repeating units of ester

  4. monomer of ether


Correct Option: C
Explanation:

Polyester is a category of polymers that contain ester in their main chain.


 Polyesters are used to make bottles, films, holograms, filters, dielectric film for capacitors, film insulation for wire and insulating tapes.

Hence the correct option is C.

______ is a popular polyester.

  1. Plastic

  2. Polythene

  3. Rayon

  4. Terylene


Correct Option: D
Explanation:

Terylene is a popular  trademark of synthetic polyester fibre. The fabric is based on terephthalic acid, characterized by lightness and crease resistance and used for clothing, sheets, ropes, sails, etc. 

PET is a familiar form of:

  1. plastic

  2. polyester

  3. acrylic

  4. rayon


Correct Option: B
Explanation:

PET is a very familiar form of polyester. PET is used for making bottles.

Which type of cloth dries faster in rainy season?

  1. Cotton

  2. Wool

  3. Polyester

  4. Silk


Correct Option: C
Explanation:

Synthetic fibres like polyesters dry up quickly.

Arrange the following fibers in the order of increasing strength:

Nylon, Cotton, Wool, Polyester, Silk

  1. Silk, Wool, Cotton, Nylon, Polyester

  2. Wool, Silk, Cotton, Nylon, Polyester

  3. Cotton, Silk, Wool, Nylon, Polyester

  4. Nylon, Cotton, Silk, Wool, Polyester


Correct Option: B
Explanation:

Tensile strength of polymer increases with increase in chain length and cross-linking of polymer chains. According to this, the tensile strength of wool < silk < cotton < nylon < polyester. Artificial fibers like nylon and polyester are designed specially to have more tensile strength.

Why PET is increasingly used for making bottles, jars and utensils?

  1. It is light weight and very strong

  2. It is shatter proof

  3. Impact resistant

  4. All of the above


Correct Option: D
Explanation:

PET is light weight, naturally colourless with high transparency, strong and impact resistant. It is shatter proof. All these properties of PET makes a highly more suitable material than glass for making bottles, jars, utensils etc.

A common form of polyester is :

  1. Nylon

  2. Rayon

  3. PET

  4. Acrylic


Correct Option: C
Explanation:

A common form of polyester is PET.

Polyester is a natural fiber.

  1. True

  2. False


Correct Option: B
Explanation:

Polyester is a synthetic fiber.

Nylon has high elasticity and tensile strength.
  1. True

  2. False


Correct Option: A
Explanation:

Nylon is a synthetic thermoplastic linear polyamide-based polymer. 


It is used for a variety of applications to include clothing, reinforcement in rubber material like car tires, for use as a rope or thread, and for a number of injection molded parts for vehicles and mechanical equipment. 


It is exceptionally strong, relatively resistant to abrasions and moisture absorptivity, long-lasting, resistant to chemicals, elastic and easy to wash. 

It is the plastic of choice for components in the engine compartment of vehicles because of its high tensile strength, temperature resilience, and chemical compatibility.

Therefore, option A is correct.

State whether true or false :

Ropes made by rayon are used in cranes and elevators.

  1. True

  2. False


Correct Option: B
Explanation:
Rayon is a manufactured fiber made from regenerated cellulose fiber. 

It is made from purified cellulose, primarily from wood pulp, which is chemically converted into a soluble compound. 

Because rayon is manufactured from naturally occurring polymers, it is considered a semisynthetic fiber and the strength is not enough that can withstand high stress to be used in cranes and elevators like metal ropes.

Therefore, option B is correct

Ropes made of _______ are used in cranes and lifts.

  1. rayon

  2. nylon

  3. acrylic

  4. spandex


Correct Option: B
Explanation:

Nylon ropes are used in cranes and lifts because of high tensile strength and elasticity of nylon.


Nylon is the strongest of all ropes in common use. It is used for absorbing shock loads, such as when lifting or towing because it has the ability to return to it's original length after being stretched. 

It also has good abrasion resistance and can last several times longer than natural fibres.

Therefore, option B is correct.

Nylon is obtained from :

  1. coal

  2. air

  3. water

  4. all of the above


Correct Option: D
Explanation:

Nylon was the first fully synthetic fibre obtained from coal, water and air.

Name the plastic whose sheets are used for packing liquids.

  1. Polythene

  2. Polycot

  3. Polywool

  4. Polyester


Correct Option: A
Explanation:
In order to pack the liquids, Polyethylene terepthalate is used.

It is an important substance that can store the liquid without leakage.

It is a polymer of ethylene terepthalate and is quite durable in carrying the stuff from one place to another.

Strength and durability are the two important factors that make it an important choice.

Hence, the correct option is $\text{A}$
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