Chapter 3 Synthetic Fibres And Plastics

Question 1. Pick the synthetic fibre out of the following?

(a) Cotton

(b) Nylon

(c) Jute

(d) Wool

Question 2. Which of the following is a source of rayon?

(a) Wool

(b) PET

(c) Wood pulp

(d) Silk

Question 3. Polycot is obtained by mixing

(a) nylon and wool

(b) polyester and wool

(c) nylon and cotton

(d) polyester and cotton

Question 4. Which is a thermosetting plastic?

(a) Melamine

(b) Polythene

(c) PVC

(d) Nylon

Question 5. The material similar to silk in appearance is

(a) Nylon

(b) Rayon

(c) Polyester

(d) Terylene

Question 6. The most suitable material for the preparation of handles of cooking utensils is

(a) Polythene

(b) PVC

(c) Nylon

(d) Bakelite

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

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

(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)

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

Question 10. The material which is commonly used for making kitchen containers is

(a) PVC

(b) Acrylic

(c) Teflon

(d) PET

Question 11. Cotton is a natural polymer. What is its chemical name?

Question 12. A synthetic fiber which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?

Question 13. Terrycot is made by mixing two types of fibres. Write the names of the fibres.

Question 14. Plastic articles are available in all possible shapes and sizes. Can you tell why?

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?

Question 16. Why is it not advisable to burn plastic and synthetic fabrics?

Question 17. Select the articles from the following list which are biodegradable.

(a) paper

(b) woolen clothes

(c) wood

(d) aluminium can

(e) plastic bag

(f) peels of vegetables

Question 18. A bucket made of plastic does not rust like a bucket made of iron. Why?

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?

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?

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?

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 ______.

Question 23. Match items in List A with the items of list B.

Question 24. Unscramble the jumbled words given below, related to synthetic materials.

(a) anory

(b) lopmery

(c) relyteen

(d) laspict

(e) yespolter

(f) felton

Question 25. Indicate whether the following statements are True or False. Also write the false statements in their correct form.

(i) The fabric terywool 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.

Question 26. Write the importance of synthetic polymers in our life.

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?

Question 28. Write an activity to show that synthetic fibres are stronger than the cotton fibres.

Question 29. Complete the crossword given below with the help of clues.

Across

1. Substance used as synthetic wool (7)

2. A plastic used for making containers and carry bags (9)

3. Substance made up of large number of smaller molecules (7)

4. Another name for this compound is artificial silk (5)

Down

5. A type of fibre obtained naturally from cocoon (4)

6. A synthetic fibre classified as polyester (8)

7. A polymer used for making rope (5)