Friday, 17 August 2018

CBSE Class 8 - Science - Synthetic Fibres and Plastics (MCQs) - NCERT Exemplar Answers (#cbsenotes)(#eduvictors)

Synthetic Fibres and Plastics


Multiple Choice Questions

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              │
├────────────────────┤
│ (a) Nylon    │(i)Thermoplastic      │
├────────────────────┤
│ (b) PVC      │(ii)Thermoplastic     │
├────────────────────┤
│ (c) Bakelite │(iii)Fibre                  │
└────────────────────┘

Codes
(a) (a)-(ii), (b)-(iii), (c)-(i)
(b) (a)-(iii), (b)-(i), (c)-(ii)
(c) (a)-(ii), (b)-(i), (c)-(iii)
(d) (a)-(iii), (b)-(ii), (c)-(i)


Question 9: Which of the following groups contains all synthetic substances?

(a) Nylon, tprylene, 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 and jute bags are better choice than polythene bags because they are:

(a) attractive
(b) cheaper
(c) eco-friendly
(d) colourful


Answers:
1: (b) Nylon
Explanation: It is a synthetic fibre. It is made without using any natural raw material. Cotton, jute and wool are natural fibres.

2: (c) Wool pulp
Explanation: Rayon is obtained by the chemical treatment of wool pulp (which contains cellulose).

3: (d) Polyster and cotton
Explanation: Polycot is obtained by mixing polyester and cotton. Polycot = polyester + cotton

4: (a) Melamine
Explanation: Melamine is a thermosetting plastic which when moulded once, cannot be softened by heating.

5: (b) Rayon
Explanation: Rayon resembles silk in appearance, therefore, rayon is also called artificial silk.

6: (d) Bakelite
Explanation: Bakelite is used for making the handles of various cooking utensils because it is a poor conductor of heat and does not become soft on getting heated.

7: (d) Good conductor of electricity
Explanation: Plastics are non-reactive, light in weight and durable but they do not conduct electricity.

8: (c) (c) (a)-(ii), (b)-(i), (c)-(iii)
Nylon —-> Fibre , PVC —->Thermoplastic , Bakelite —->Thermosetting plastic

9: (c) PVC, polythene, bakelite
Explanation: PVC, polythene and bakelite are synthetic substances.

10: (d) PET
Explanation: PET is ‘poly-ethylene’ terephthalate’ PET as a plastic is very light weight and is commonly used for making kitchen containers.

11: (c) eco-friendly
Explanation: Cotton and jute are natural fibres and are bio-degradable.