Question

This section contains multiple choice questions. Each question has 4 choices (a), (b), (c) and (d), out of which ONLY ONE is correct. Natural rubber is a polymer of (a) chloroprene (b) isoprene (c) butadiene (d) styrene

Short answer

Short Answer: The correct monomer that forms the natural rubber polymer is (b) isoprene, as it forms the polymer known as polyisoprene, which is the main constituent of natural rubber.

Step-by-step solution

Recalling the structure of natural rubber

Natural rubber is an organic compound made up of a long chain of monomers. It is a type of polymer, meaning it is formed from multiple identical monomers. Recall the structure of natural rubber and recognize the monomers it is formed from.

Identifying the correct monomer

Now, look at the given options and recall their structures: (a) Chloroprene - It is a monomer used to form neoprene, which is a synthetic rubber and not natural rubber. (b) Isoprene - It is a monomer that forms the polymer known as polyisoprene, which is the main constituent of natural rubber. (c) Butadiene - It is a monomer used to form synthetic rubbers like polybutadiene and styrene-butadiene rubber, but not natural rubber. (d) Styrene - It is a monomer used to form polystyrene, which is a plastic material and not a rubber compound.

Select the correct answer

After analyzing the options, it is clear that Isoprene(b) is the only correct choice as it forms the natural rubber polymer, polyisoprene. Therefore, the correct answer is option (b) isoprene.

Key concepts

Polyisoprene

Natural rubber is an essential material used extensively in various industries, primarily because of its elasticity, resistance to abrasion, and waterproof properties. The key to these characteristics lies in its chemical structure, which consists of a polymer called polyisoprene.

At its core, polyisoprene is a long chain-like molecule made up of many repeating units. Each unit is a molecule of isoprene, the monomer of polyisoprene. In chemistry, a polymer is a large molecule composed of repeating subunits, and in the case of natural rubber, each of these subunits is an isoprene molecule linked together in a head-to-tail fashion.

Properties of Polyisoprene

When considering its properties, polyisoprene exhibits excellent elasticity, which is the ability to return to its original shape after being stretched or compressed. This property is what makes natural rubber so valuable in products that require flexibility, such as tires, elastic bands, and gloves. Its flexibility is due to the twisted and coiled polymer chains that can easily be stretched but will return to their original shape when the force is released.

Furthermore, polyisoprene is also biodegradable, which makes it an environmentally friendly material as compared to synthetic polymers that may persist in the environment for much longer.

Monomer Identification

Understanding the basic building block of a polymer is crucial in fields like materials science and organic chemistry. The process of identifying the monomer in a polymer is what we refer to as monomer identification.

For natural rubber, the monomer identification is relatively straightforward. In the example provided, we were tasked with finding the correct monomer that forms natural rubber from a list of options. The correct identification involves recalling the structure of various potential monomers and knowing the specific structure of the natural polymer.

How to Identify the Monomer?

To identify the monomer, you would look for the fundamental molecular unit that is repeated throughout the polymer chain. The monomer of natural rubber is isoprene, which is a simple organic compound with the chemical formula \( C_5H_8 \). Once identified, understanding the reactive nature of isoprene allows chemists to replicate or modify the polymerization process that occurs in nature, leading to the production of synthetic rubber and other polyisoprene derivatives.

This identification process is fundamental to synthesizing new materials and for understanding the behavior of existing ones in various conditions.

Organic Chemistry

Organic chemistry is the branch of chemistry that deals with the structure, properties, composition, reactions, and preparation of carbon-containing compounds, which not only include hydrocarbons but also compounds with any number of other elements, including hydrogen, nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur.

This field of chemistry is fundamental when talking about natural rubber. It allows scientists to understand the molecular structure of polyisoprene, the relationships between molecular structure and material properties, and how different environmental factors may lead to changes in these properties.

Role in Everyday Materials

Practically speaking, organic chemistry enables the creation of a myriad of materials we encounter in our daily lives. For example, the formulation of synthetic alternatives to natural rubber, improvements to the quality and durability of rubber, and tailored polymers for specific applications are all possible thanks to the principles discovered and utilized within organic chemistry.

Through continued study and manipulation of carbon-based molecules, organic chemistry contributes significantly to the advancement of materials science and, by extension, to improvements in technology, healthcare, and environmental preservation.