Question

Which of the following is a thermosetting polymer?
A.Buna-N
B.PVC
C.Bakelite
D.Nylon-6

Answer 1

Hint:Polymers are macromolecules which are formed by the repetition of a molecule which is known as a monomer and the chain of these monomers is known as a polymer. They are classified on the basis of molecular forces between their molecules and are categorised as thermosetting polymers which have cross linking and are branched and once heated, they cannot return to their original state.

Complete answer:
Polymers are a chain of large molecules which have high molecular mass. They are known as macromolecules which are formed by the repeated joining of units of molecules. The molecule which is repeated in order to form long chains of molecules called polymers is known as a monomer. This process of formation polymers is known as polymerisation. Polymers are classified into different categories on the basis of the source of polymers, their structures, mode of polymerisation, growth of polymers and most importantly they are categorised on the basis of their molecular forces.
Thermosetting polymers are polymers which are classified on the basis of the molecular forces between their molecules. They have cross linking between their molecules and are heavily branched. These polymers cannot be reduced. When these polymers are heated or are exposed to conditions like high pressure or radiation then, they are hardened due to extensive cross linkage and this is irreversible.
For the given question,
The most common example of thermosetting polymers is Bakelite. It is a cross linked polymer which on heating cannot be reversed to its original structure and thus, it is a thermosetting polymer.

Thus, the correct option for the above question is (C) Bakelite.

 Note:
Bakelite is a thermosetting polymer which has high resistance to electricity and heat and is therefore used for various industrial purposes. It is used in electrical appliances due to its good insulating properties and it is also used for producing kitchenware.