Question

Which can be used as monomer in a polymerization reaction? (a) \(\mathrm{C}_{2} \mathrm{H}_{4}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{6}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl}\)

Short answer

\(\mathrm{C}_{2} \mathrm{H}_{4}\) can be used as a monomer in a polymerization reaction.

Step-by-step solution

Understanding Monomer Characteristics

Monomers need to have a functional group or double bond that allows them to undergo polymerization reactions. In addition, they should be able to link together to form repeated structural units.

Identifying Functional Groups

Review each option to determine if it contains a functional group or feature that allows polymerization:(a) \(\mathrm{C}_{2} \mathrm{H}_{4}\) has a double bond (alkene).(b) \(\mathrm{C}_{2} \mathrm{H}_{6}\) is an alkane with only single bonds.(c) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\) has a chlorine substituent but no double bond.(d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl}\) is a chlorobenzene, which contains an aromatic ring.

Evaluating Polymerization Potential

For each option, assess if it can act as a monomer in polymerization based on its structure: (a) \(\mathrm{C}_{2} \mathrm{H}_{4}\) can participate in addition polymerization due to its double bond, forming polymers like polyethylene.(b) \(\mathrm{C}_{2} \mathrm{H}_{6}\) cannot polymerize as all bonds are single.(c) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\) lacks a double bond or other polymer-forming functionality.(d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl}\) does not typically act as a monomer in polymerization.

Conclusion

Only \(\mathrm{C}_{2} \mathrm{H}_{4}\) has the structural feature necessary for polymerization, making it a suitable monomer for such reactions.

Key concepts

Monomer

A monomer is like a building block. It’s the most crucial part of the polymer puzzle. Monomers are small, simple molecules that have the ability to connect, or "link," with other monomers. Together, they form large molecules known as polymers. Think of it like linking Lego bricks together to build a larger structure.

To qualify as a monomer in polymerization reactions, a molecule must have specific characteristics. One such requirement is the presence of a functional group or a feature such as a double bond. This feature permits bonding with other monomer molecules, enabling the formation of long chains. Not every molecule out there can be a monomer. It's key to understand which molecules have this potential when studying polymer chemistry.

Functional Groups

Functional groups are special clusters of atoms within molecules that define much of their behavior during chemical reactions. Think of them as the "personality traits" of molecules. They determine what the molecule can do and what reactions it can participate in.

In the world of polymers, a functional group can make or break the ability of a monomer to polymerize. For example, a molecule like ethylene ( ext{C}_{2} ext{H}_{4} ) has a carbon-carbon double bond, which is a functional group that enables it to engage in reactions leading to polymerization. Without the right functional group, a molecule might not have the reactivity needed to connect into long chains, meaning it won't be useful for making polymers.

Addition Polymerization

Addition polymerization is a process where monomers add together without the loss of any small molecules like water. It’s one of the main ways polymers are synthesized and it’s pretty straightforward! Picture it as a grand chain-building activity where each monomer adds itself into the growing chain directly.

This type of polymerization is particularly common with monomers that have double bonds. During the process, these double bonds "open up," allowing each monomer to connect to the next. Ethylene, for example, undergoes addition polymerization to form polyethylene, a versatile plastic used in countless everyday items. It's a fascinating process because it shows how simple molecules join forces to create something much more complex and useful.

Alkenes

Alkenes are a fascinating class of hydrocarbons. They have at least one carbon-carbon double bond that makes them quite reactive. This double bond is often the key feature utilized during polymerizations, especially in addition polymerization.

The structure of alkenes makes them ideal candidates for polymerization. For instance, ethylene, an alkene, is often used as a monomer to form polyethylene. The double bond in ethylene breaks and forms new bonds with other ethylene molecules, linking them into long polymer chains.

Alkenes are integral to many chemical processes, not just polymerization. But their role in polymerization schemes makes them particularly important when learning about and making polymers. Their reactivity and structure are always worth keeping in mind when studying chemistry.