Question

A) Natural rubber is an elastomer.
R) The intermolecular forces of attraction between the polymer chains are weak Van der Waals forces.
A.Both A and R are correct and R is the correct explanation of A.
B.Both A and R are correct but R is not the correct explanation of A.
C.A is correct but R is incorrect.
D.A is incorrect but R is correct.

Answer 1

Hint:Elastomer is a type of polymer. Polymers are macromolecules formed by joining small molecules together. Intermolecular forces like Van der Waals forces are present in them. Van der Waals forces are weak in nature.

Complete answer:
-Polymers are high molecular weight compounds that are formed by the combination of small molecules called monomers. The process by which polymers are formed from small monomers is called polymerisation. Polymers occur naturally as well as artificially prepared.
-Natural rubber is a type of polymer. These types of polymers have wide applications in different fields due to their mechanical properties like elasticity, tensile strength. These mechanical properties are controlled by intermolecular forces like weak Van der Waals forces. These are the forces that help to bind the polymer chains.
-Natural rubber is an elastomer. These Elastomers are solid in nature. In these polymers, the polymer chains are held together by weak Van der Waals forces. Due to these weak binding forces the polymer can be stretched. Such elastomers have very low values of tensile strength.
-Hence, we can say that statement A is correct and statement R is the correct explanation of A.
So the correct option is A.

Note:
Van der Waals forces are weak intermolecular forces present in elastomers. Elastomer is a type of polymer classified on the basis of the magnitude of intermolecular forces present in the polymers. Other examples of elastomers are Buna-S, Buna-N, Neoprene. Sometimes cross-links are introduced in the molecule which help the polymer to revert back to its original position.