Multiple Choice Questions...................
Question 1: Pick the synthetic fibre out of the following?
(a) Cotton
(b) Nylon
(c) Jute
(d) Wool
Solution 1: (b) Nylon
Cotton and Jute come from trees, Wool comes from animals, and Nylon is a synthetic fibre.
Question 2: Which of the following is a source of rayon?
(a) Wool
(b) PET
(c) Wood pulp
(d) Silk
Solution 2: (c) Wood pulp
Rayon is made from wood pulp that has been chemically prepared.
Question 3: Polycot is obtained by mixing
(a) nylon and wool
(b) polyester and wool
(c) nylon and cotton
(d) polyester and cotton
Solution 3: (d) polyester and cotton
By mixing polyester and cotton polycot is obtained.
Question 4: Which is a thermosetting plastic?
(a) Melamine
(b) Polythene
(c) PVC
(d) Nylon
Solution 4: (a) Melamine
Thermosetting plastics cannot be softened by heating after they have been moulded. Bakelite and melamine are two examples.
Question 5: The material similar to silk in appearance is
(a) Nylon
(b) Rayon
(c) Polyester
(d) Terylene
Solution 5: (b) Rayon
Rayon is made from wood pulp that has been chemically prepared. Rayon is less costly than silk and can be woven in the same way.
Question 6: The most suitable material for the preparation of handles of cooking utensils is
(a) Polythene
(b) PVC
(c) Nylon
(d) Bakelite
Solution 6: (d) Bakelite
Bakelite is a weak heat conductor and does not soften when heated, so it is used to make the handles of cooking utensils.
Question 7: Which of the following is not a common property of plastics?
(a) Non-reactive
(b) Light in weight
(c) Durable
(d) Good conductor of electricity
Solution 7: (d) Good conductor of electricity
Plastic is a weak electrical conductor.
Question 8: Which of the following represents the correct match for items in Column A with those in Column B.
Column A – Column B
I. Nylon – (i) Thermoplastic
II. PVC – (ii) Thermosetting plastic
III. Bakelite – (iii) Fibre
choose the option
(a) I-(ii), II-(iii), III-(i)
(b) I-(iii), II-(i), III-(ii)
(c) I-(ii), II-(i), III-(iii)
(d) I-(iii), II-(ii), III-(i)
Solution 8: (c) I-(ii), II-(i), III-(iii)
Question 9: Which of the following groups contain all synthetic substances?
(a) Nylon, Terylene, Wool
(b) Cotton, Polycot, Rayon
(c) PVC, Polythene, Bakelite
(d) Acrylic, Silk, Wool
Solution 9: (c) PVC, Polythene, Bakelite
Wool is derived from an animal source in both options a) and c).
Choice b) includes cotton, which comes from a farm.
As a result, the right answer is (c) PVC, Polythene, and Bakelite.
Question 10: The material which is commonly used for making kitchen containers is
(a) PVC
(b) Acrylic
(c) Teflon
(d) PET
Solution 10: (d) PET
PET, or polyethylene tetra thalate, is a lightweight material that is widely used in the manufacture of kitchen containers.
Very Short Answer Questions.............
Question 11: Cotton is a natural polymer. What is its chemical name?
Solution 11: Cotton is a natural polymer. Cellulose is the chemical name of cotton.
Question 12: A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?
Solution 12: Rayon is a type of synthetic silk.
Question 13: Terrycot is made by mixing two types of fibres. Write the names of the fibres.
Solution 13: Terrycot is made from a mixture of terylene and cotton.
Question 14: Plastic articles are available in all possible shapes and sizes. Can you tell why?
Solution 14: Since it is so simple to make moulds out of plastic, it is available in a wide variety of shapes and sizes.
Question 15: Plastic is used for making a large variety of articles of daily use and these articles are very attractive. But it is advised to avoid the use of plastic as far as possible. Why?
Solution 15: Plastic is not biodegradable, and disposing of it is a serious problem. As a consequence, it is recommended that you use plastic as little as possible.
Question 16: Why is it not advisable to burn plastic and synthetic fabrics?
Solution 16: When plastic is burned, poisonous gases are released into the atmosphere, polluting the environment. As a result, burning plastic and synthetic materials is not recommended.
Question 17: Select the articles from the following list which are biodegradable.
(a) Paper
(b) Woollen clothes
(c) Wood
(d) Aluminium can
(e) Plastic bag
(f) Peels of vegetables
Solution 17:
(a) Paper
(b) Woollen clothes
(c) Wood
(d) Peels of vegetables
Question 18: A bucket made of plastic does not rust like a bucket made of iron. Why?
Solution 18: Plastic is a chemically inert element. It must react with water and oxygen to form rust. As a result, plastic does not rust.
Short Answer Questions...........................
Question 19: Rohit took with him some nylon ropes when he was going for rock climbing. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute?
Solution 19: As compared to jute and cotton ropes, nylon ropes are sturdy, flexible, and elastic.
Acrylic blankets are affordable, lightweight, and sturdy, and come in a range of colours and patterns. They are easy to clean at home.
Question 20: A lady went to the market to buy a blanket. The shopkeeper showed her blankets made of acrylic fibres as well as made of wool. She preferred to buy an acrylic blanket. Can you guess why?
Solution 20: Acrylic blankets are preferred by ladies over wool blankets because they are less costly, lighter in weight, more sturdy, and come in a range of colours and designs. They are easy to clean at home.
Question 21: PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Can you write the major difference between these two types of plastics?
Solution 21: Thermoplastics deform when heated, making them easy to bend. Thermosetting plastics, on the other hand, cannot be softened by heating.
Question 22: Fill in the blanks.
(i) A polymer is a chain of many small units joined together which are called ______.
(ii) The synthetic fibres are also known as ______ fibres.
(iii) The first fully synthetic fibre was ______.
(iv) A fibre similar to wool is ______.
(v) A plastic used for making crockery is ______.
Solution 22:
(i) A polymer is a chain of many small units joined together which are called monomers.
(ii) The synthetic fibres are also known as man-made fibres.
(iii) The first fully synthetic fibre was Nylon.
(iv) A fibre similar to wool is acrylic.
(v) A plastic used for making crockery is melamine.
Question 23: Match items in List A with the items of list B.
Solution 23:
Question 24: Unscramble the jumbled words given below, related to synthetic materials.
(a) anory
(b) lopmery
(c) relyteen
(d) laspict
(e) yespolter
(f) felton
Solution 24:
(a) Rayon
(b) Polymer
(c) Terylene
(d) Plastic
(e) Polyester
(f) Teflon
Long Answer Questions...........................
Question 25: Indicate whether the following statements are True or False. Also, write false statements in their correct form.
(i) The fabric terry wool is obtained by mixing terylene and wool.
(ii) Synthetic fibres do not melt on heating.
(iii) It is risky to wear synthetic clothes while working in the kitchen.
(iv) Most of the plastics are biodegradable.
Solution 25:
i) True
ii) False- On heating Synthetic fibres use to melt.
iii) True
iv) False- Plastics are always non-biodegradable.
Question 26: Write the importance of synthetic polymers in our life.
Solution 26: Following are the points to justify the importance of synthetic polymers in our life.
1. Nylon
It's used to make rock climbing ropes, fishing nets, raincoats, parachutes, and tyre cords, among other items.
2. Acrylic
It's used in sweaters, tracksuits, boot and glove linings, and upholstery fabrics and carpets.
3. Terylene
It's used to produce sarees, tapestries, and dress material in the garment industry. It's also blended with natural fabrics like cotton and wool to produce a broader range of clothing choices.
4. Plastics
Meat, water, milk, pickles, dry fruit, and other things are kept in it. Plastic containers tend to be the most functional. In contrast to metals, this is due to the lightweight, low cost, good power, and ease of handling. Plastic is used in vehicles, aircraft, and spacecraft.
Question 27: Despite being very useful it is advised to restrict the use of plastic. Why is it so? Can you suggest some methods to limit its consumption?
Solution 27: Plastic is a non-biodegradable substance that presents a major environmental hazard. The most important issue we face in regretting our use of plastics is disposing of its waste. When plastics are burned, they pollute the soil and the air.
Plastic use should be decreased, and used plastic should be recycled and reused to cut down on waste.
Question 28: Write an activity to show that synthetic fibres are stronger than the cotton fibres.
Solution 28: Take a clamp and an iron stand. Take a cotton thread with a length of around 60 cm. As shown in Figure below, tie it to the clamp so that it hangs freely from it. Suspend a pan from the free end so that weight can be dropped in it. One by one, add weight before the thread splits. Make a note of how much weight is needed to break the thread. This weight signifies the fiber's tensile strength. Repeat the procedure with wool, polyester, silk, and nylon threads.
Question 29: Complete the crossword given below with the help of clues
Solution 29:
