Question

Among cellulose, polyvinyl chloride, nylon and natural rubber, the polymer in which the following intermolecular force of attraction is weakest?

• A. nylon
• B. polyvinyl chloride
• C. cellulose
• D. natural rubber

Answer 1

Answer: (D)

natural rubber

The word 'polymer' is coined from two Greek words : poly means many and mer means unit or part. The term polymer is defined as very large molecules having high molecular mass.

Classification of polymers $\to$

On the basis of molecular forces $\to$ A large number of polymer applications in different fields depend on their unique chemical properties like tensile strength, elasticity, toughness, etc.

These properties are governed by intermolecular forces. Eg - van der Waal forces and hydrogen bonds. Under this category, the polymers are classified into four subgroups $\to$

(1) Elastomers - In these polymer chains are held together by the weakest intermolecular forces. These weak binding forces permit the polymer to be stretched.

(2) Fibres - Fibres are the thread forming solids which possess high tensile strength and high modulus. In these polymers, there is strong intermolecular forces like H-bonds.

Example $\to$ Nylon 6,6, terylene, etc.

(3) Thermoplastic polymers $\to$ These polymers possess intermolecular forces of attraction intermediate between elastomers and fibres.

Example - Polyvinyl chloride, polythene, etc.

(4) Thermosetting polymers - These polymers are cross-linked or heavily branched molecules, which on heating undergo extensive cross-linking in moulds.

Example $\to$ Bakelite

Hence, among nylon, polyvinyl chloride and cellulose and natural rubber; natural rubber is the polymer in which the intermolecular force in weakest.

So, the correct option is (D).