Question

The non-metal used to treat rubber in the process of vulcanization is :
(A) sulphur
(B) phosphorus
(C) carbon
(D) chloride

Answer 1

Hint: Understand the process of formation of rubber from its monomer and the need for vulcanization. Vulcanization basically makes the rubber hard making it more durable. So the non-metal must have the ability to form bonds with long rubber chains to create an interlink between them and hence making the rubber as a whole strong.

Complete step by step answer:
Polymerization is a process of reacting monomer molecules together in a chemical reaction to form long polymer chains .
In chemical compounds, polymerization can occur by various types of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and the steric effects that are present.
Natural rubber is formed by the polymerization reaction of isoprene molecules. Thus, the monomer of rubber is the compound isoprene.
However, the tensile strength of natural rubber is less along with low elasticity. This is not suitable for motor tires. This is the reason why we add the non-metal sulphur in small amounts.
The process of addition of sulphur to natural rubber thereby making the polymer strong and more elastic is called vulcanization. The polymer thus formed is called vulcanized rubber.
So, the correct answer is “Option A”.

Note: It is important to know that sulphur atoms do not interfere with the polymerisation reaction of isoprene molecules. Instead sulphur reacts with long chains or rubber strands thus creating a link between the adjacent strands thereby making the polymer as a whole strong.