Question

Natural rubber is a polymer of

• A. butadiene
• B. ethyne
• C. styrene
• D. isoprene

Hint:

The monomer of natural rubber is Isoprene. Polyisoprene, a polymer of isoprene (C5H8) is the primary chemical constituent of natural rubber.

Answer 1

The Correct Option is D

Natural rubber is a polymer that is derived from the monomer isoprene. It is primarily composed of repeating units of isoprene, also known as 2-methyl-1,3-butadiene. Let's explore this in detail:

• Understanding Polymerization: Polymerization is a chemical reaction in which small molecules called monomers join together to form a long-chain polymer. For natural rubber, the monomer is isoprene.
• Structure of Isoprene: Isoprene has the chemical formula C₅H₈ and is an unsaturated hydrocarbon, specifically a diene, due to the presence of two carbon-carbon double bonds.
• Formation of Natural Rubber: During polymerization, the double bonds in isoprene open up and form bonds with other isoprene units, resulting in the polymer known as polyisoprene, which constitutes natural rubber.

Let's now evaluate why isoprene is the correct answer and rule out other options:

1. Butadiene: While butadiene is used to make synthetic rubber like Buna-S and Buna-N, it is not the monomer for natural rubber.
2. Ethyne: Also known as acetylene, ethyne is used in welding and as a precursor in some chemical synthesis but is not related to natural rubber formation.
3. Styrene: Styrene is used to produce polystyrene, a different synthetic polymer, not related to natural rubber.

Therefore, the correct answer is isoprene, as it is the monomer from which natural rubber is polymerized. This explanation highlights the relevant chemistry involved in understanding natural rubber's composition and refutes the other options logically.