Olympiad Science - Synthetic Fibres and Plastics
Exam Duration: 45 Mins Total Questions : 30
What is the process of taking out silk threads from the-cocoon known as?
- (a)
Rearing
- (b)
Sorting
- (c)
Scouring
- (d)
Reeling
Reeling is the extracting of silk threads from cocoons.
What do silk fibres consist of?
- (a)
Vitamins
- (b)
Carbohydrates
- (c)
Proteins
- (d)
Fats
The caterpillar secretes a protein called fibroin which hardens on exposure to air and become silk fibres
Which of these provide compounds necessary to prepare nylon?
- (a)
Only (i)
- (b)
Only (i) and (ii)
- (c)
Only (i) and (iii)
- (d)
(i), (ii) and (iii)
Nylon is the first, fully, synthetic fibre obtained from coal, air and water
Why is nylon useful?
- (a)
It is soft, strong and light.
- (b)
It is transparent, light and easy to wash
- (c)
It is strong, elastic and light.
- (d)
It is soft, inexpensive and strong.
Nylon fibre is strong, elastic and light. It is lustrous and easy to wash. So, it became very popular for making clothes.
Which of the following statements is NOT true?
- (a)
Fabric is made of yarn.
- (b)
Jute is the outer covering of the coconut
- (c)
Polyester is a synthetic fibre.
- (d)
Silk fibre is obtained from silkworms
Jute is made from the inner fibre of the stem. Coconut fibre is the outer covering of the coconut
Fruits have characteristic smells. Which of these chemicals is responsible for it?
- (a)
Yeas
- (b)
Alcohol
- (c)
Cellulose
- (d)
Esters
Esters are responsible for the characteristic smell of fruits.
Which of the following is made from coconut fibre?
- (a)
Sweaters
- (b)
Shoes
- (c)
Mattresses
- (d)
Sarees
Mattresses are made from coconut fibres
Which of the following statements is NOT true?
- (a)
Polymers occur in nature.
- (b)
Nylon is used in the making of parachutes.
- (c)
Cellulose is made up of glucose units.
- (d)
Nylon thread is weaker than cotton thread
The nylon thread is stronger than the cotton thread
PVC is an example of
- (a)
plastic.
- (b)
thermoplastic
- (c)
thermosetting plastic.
- (d)
acrylic
Thermoplastic is a type of plastic that can be softened or bent easily by heating and hardened by cooling
e.g., PVC,Polythene etc
Which of the following properties of plastic makes it most convenient for use?
- (a)
It is non-reactive.
- (b)
It is light, strong and durable.
- (c)
It is easily remouldable .
- (d)
All of the above
Plastic is non-reactive, light, strong and durable. It is easily remouldable. All these properties make plastic most convenient for its use.
Which of the given materials is used to prepare synthetic fibres like polyester and acrylic?
- (a)
Wood pulp
- (b)
Coconut fibres
- (c)
Petrochemicals
- (d)
Paper pulp
Most of the synthetic fibres are prepared from petrochemicals
Which of the following is nonbiodegradable?
- (a)
Plastic
- (b)
Cotton
- (c)
Paper
- (d)
Left-over food
Plastic,metal cans,etc.. are the materials which cannot be decomposed by natural processes.Hence, they are non-biodegradable.
By which of these processes is polythene produced?
- (a)
Isomerization
- (b)
Polymerisation
- (c)
Hydrogenation
- (d)
All of the above
Polythene is formed by the polymerisation of ethylene. Polymerisation is a process in which molecules of the same or different compounds are joined together to form a long chain of molecules called polymers.
Which of the following products cannot be decomposed easily?
- (a)
Acrylic
- (b)
Polythene
- (c)
Plastic
- (d)
All the above
All synthetic products/chemicals are non-biodegradable and cannot be decomposed easily.
Why is plastic coated with melamine?
- (a)
It becomes a good conductor of heat.
- (b)
It becomes strong and flexible.
- (c)
It becomes a fire proof plastic.
- (d)
It is remouldable
Plastic when coated with melamine becomes fire proof. These materials are used for preparing fabrics for fire-men, and making kitchen ware etc.
Which of the following is used for making terylene fibres?
- (a)
Wood pulp
- (b)
Esters
- (c)
Acrylic
- (d)
Paper pulp
Terylene fibres are made up of chemical substances called esters.
To which of the following does the 4R principle apply the most?
- (a)
Synthetic fibre
- (b)
Natural fibre
- (c)
Metal
- (d)
Plastic
The 4R principle i.e.,reduce, reuse,recycle and recover applies for plastic
Which of the following statements is NOT true?
- (a)
Thermosetting plastics are bad conductors of heat and electricity.
- (b)
Thermoplastics are good conductors of heat and electricity
- (c)
Plastics do not get corroded easily.
- (d)
Plastic is also a polymer.
Thermoplastics are bad conductors of heat and electricity.
Which of the following is a property of thermosetting plastic?
- (a)
Flame resistant
- (b)
Non-corrosive
- (c)
Mouldable
- (d)
All of the above
Plastic as such is not flame resistant but thermosetting plastics resist fire, noncorrosive and mouldable. They can be used for making kitchen ware
Which of the following is NOT a natural polymer?
- (a)
Natural rubber
- (b)
Polyester
- (c)
Protein
- (d)
Starch
Natural polymers are polymers produced by living organisms. They include natural rubber and natural food stuffs. Polyester is a synthetic fibre (not a natural polymer).
Which of the following fabrics is made by mixing two types of fibres?
- (a)
Cotton
- (b)
Polywool
- (c)
Rayon
- (d)
Nylon
Polywool is a mixture of polyester and wool.
Which of the following differences regarding thermoplastics and thermosetts is/are true?
- (a)
Only (i)
- (b)
Only (i) and (ii)
- (c)
Only (i) and (iii)
- (d)
(i), (ii) and (iii)
Differences (i) and (iii) are true of thermoplastics and thermosetts
Which of the following properties of nylon are most convenient for its use?
- (a)
It is soft, strong and heavy.
- (b)
It is strong, elastic and light.
- (c)
It is soft, inexpensive and strong.
- (d)
It is expensive, soft and light.
Nylon is strong, elastic and light
Which of the following is an example of a heavily cross linked polymer?
- (a)
Melamine
- (b)
Polythene
- (c)
Nylon
- (d)
Polyester
Melamine is an example of thermoset plastics. Thermoset plastics are heavily cross-linked polymers and hence, they are rigid
How does the burning of synthetic polymers such as plastic pollute the environment?
- (a)
By releasing smoke and toxic gases
- (b)
By releasing water vapour and haze
- (c)
By releasing water vapour and smoke
- (d)
By forming smog and rain
The burning of synthetic polymers release smoke and toxic gases which pollute the environment
Which of the following is a property of thermoplastics?
- (a)
They do not bend.
- (b)
They do not get deformed easily.
- (c)
They are resistant to most of the chemicals.
- (d)
They are made up of long polymer chains with strong bonds.
Thermoplastics are resistant to most of the chemicals. They are easy to burn, bend and do not conduct electricity and they consist of linear polymer chains
which are linked by weak attractive forces.
Which of these clothes dry faster in rainy season?
- (a)
Cotton
- (b)
Wool
- (c)
Polyester
- (d)
Silk
Synthetic fibres like polyesters absorb less water and dry up quickly.
Which of these clothes should you wear while cooking in the kitchen?
- (a)
Rayon
- (b)
Cotton
- (c)
Polyester
- (d)
Polycot
Synthetic fibres catch fire easily and melt on heating. Therefore, it is not safe to wear clothes made of synthetic fibres. So, cotton clothes are best and safe.
By what name is artificial (man-made) wool known as?
- (a)
Rayon
- (b)
Acrylic
- (c)
Polycot
- (d)
Polyester
Acrylic is an artificial wool
What is the best method to avoid pollution by using plastic bags?
- (a)
Burying the plastic bags in the soil.
- (b)
Using bags made of biodegradable material.
- (c)
Throwing the plastic bags into the river
- (d)
Burning the plastic bags in a rubbish dump.
The use of biodegradable bags is the best method to avoid pollution.