Synthetic Fibres and Plastic NCERT Solutions: This is one of the chapters in Class 8 science book ( chapter 4). This chapter discusses fibres, their origin, and plastics. I have given solutions to the back exercise questions of the NCERT book. If you have any queries you can ask me through the comments section below.
Synthetic Fibres and Plastic NCERT Solutions
Question1: Explain why some fabrics are called synthetics?
Ans 1: Those fabrics which are not obtained naturally are known as Synthetics.
Question 2: Rayon is different from synthetic fibres because?
- It has a silk-like appearance.
- It is obtained from wood pulp.
- It is obtained from wood pulp.
- Its fibers can also be woven like those of natural fibers
Ans 2: It is obtained from Wood pulp.
Must Check: Cell Structure Function NCERT Solutions
Question 3: Fill in the blanks with appropriate word
Ans 3:
a) Synthetic fibres are also called man-made or artificial fibres.
b) Synthetic fibres are synthesized from raw-materials called petrochemicals.
c) Like synthetic fibres, plastic is also a polymer.
Question 4: Give examples which indicate that nylon fibres are very strong.
Ans 4: Nylon fibres are very strong in nature. This can be judged by the fact that they are used in making the climbing ropes for mountaineers and other purposes.
Question 5: Explain why plastic containers are favoured for storing food?
Ans 5: Plastic containers can be used for longer duration. They can easily store food easily. We can keepall types of food in plastic container including liquid food items. That’s why they are preferred over other materials.
Question 6: Explain the difference between thermoplastic and thermosetting plastic.
Ans 6:
| Thermoplastics | Thermosetting plastics |
| 1. The plastics that can change their shape on heating are known as thermoplastics. 2. They are used for manufacturing cars, toys and containers. |
1. Thermosetting plastics are those that does not change their shape even if we heat them and they are irreversibly hardened.
2. Some of the examples of this type are Vulcanized rubber. Bakelite. Polyurethane.
|
7. Explain why the following things are made of thermosetting plastics.
I. Saucepan handles
Saucepan handles are made up of thermosetting plastic because they are poor conductors of heat so does person can hold things with the handles easily.
II. Electric plugs/ switches/ switchboards
They are made of thermosetting plastic because they are poor conductors of electricity and does we can prevent electric shocks. They act as insulators.
Question 8: Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Give reasons for your suggestion.
Ans 8: Cotton clothes are good to wear in summer season so Rana should buy cotton shirts. Cotton does not trap heat inside and keeps us cool. Air can easily pass through it and sweat dries up in air. Synthetic material does not do so.
Also Read: Combustion and Flame NCERT Solutions Class 8
Question 9: Give examples to show that plastics are non corrosive in nature.
Ans 9: Plastic does not suffer from corrosion even if it remains in contact with air and moisture like iron.
Question 10: Should the handle and the bristles of the toothbrush be made of the same material? Why?
Ans 10: The handles and the bristles of the tooth brush should be made from different materias as both have different functions. The bristles will be used to clean the mouth while the handle will be used to provide firm grip. Bristles should not be hard like the base of the brush else they can hurt the person’s mouth.
Question 11: Avoid plastic as much as possible. Comment on this statement
Ans 11. Plastics remain in the environment and can not be destroyed. They are non-biodegradable and harm the environment. So, we should use them less and should look for alternatives.
Question 12: Match the following correctly:
Ans. (i) Polyester: Fabrics don’t wrinkle easily
(ii) Rayon: Prepared by using wood pulp
(iii) Teflon: Used to make non-stick cookware
(iv) Nylon: Used for making parachutes and stockings
Question 13: ‘Manufacturing synthetic fibers is actually helping conservation of forests’. Comment.
Ans 13: Synthetic Fibres are made from by artificial process. Natural fibres are obtained from the animals and different plants. Like silk is obtained from silk worm, Wool is obtained from sheep etc. To obtain natural fibres animals are killed and plants are cut. This affects the nature. So, we can say that manufacturing synthetic fibers is actually helping the conservation of forests.
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