NCERT Class VIII Science Solution: Chapter 3-Synthetics Fibres and Plastics Part 3

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Question 7:

Explain why the following are made of thermosetting plastics.

  1. Saucepan handles.

As showing images is a result for Saucepan handles.

Result for Saucepan Handles

  1. Electric plugs/switches/plug boards.

As showing images is a result for electrical plugs

Result for Electrical Plugs

Answer:

  1. Melamine (a thermosetting plastics) resists fire and can tolerate heat better than other plastics. So, it is used for making Saucepan handles, which resist fire.

  2. Bakelite (a thermosetting plastics) is a poor conductor of heat and electricity. So, it is used for making Electric plugs, switches, plug boards, etc.

Question 8:

Categories the materials of the following products into ‘can be recycled’ and ‘cannot be recycled’:

Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastic bowls, and plastic covering on electrical wires, plastic chairs and electrical switches.

Answer:

Plastic toys, carry bags, ball point pens, plastic bowls, plastic covering on electrical wires and plastic chairs can be recycled as these are the thermoplastic.

Telephone instruments, cooker handles and electrical switches cannot be recycled as these are thermosetting plastics.

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