Question

Draw a line-bond structure for vinyl chloride, \(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{Cl}\), the starting material from which PVC [poly(vinyl chloride)] plastic is made.

Short answer

Vinyl chloride's line-bond structure is drawn as: CH2=CH-Cl.

Step-by-step solution

Identify the Atoms in the Molecule

Vinyl chloride consists of 2 carbon (C) atoms, 3 hydrogen (H) atoms, and 1 chlorine (Cl) atom. It's important to know the number and types of atoms to draw the structure accurately.

Understand the Structure

Vinyl chloride is an alkene with a double bond. Typically, one carbon atom (often represented as C1) is doubly bonded to another carbon atom (C2). This double bond is a key feature of the vinyl group.

Determine How Atoms are Connected

In vinyl chloride, the typical bond arrangement is C1 having a double bond with C2. The second carbon atom (C2) is bonded to a chlorine atom (Cl). Each carbon atom completes its four bonds with hydrogen atoms: C1 forms two bonds with hydrogen atoms, while C2 forms one bond with a hydrogen atom.

Sketch the Line-Bond Structure

Begin by drawing two carbon atoms connected by a double bond: C=C. Attach two hydrogen atoms to C1 (the left carbon) and one hydrogen atom to C2 (the right carbon). Lastly, attach a chlorine atom to C2. This can be drawn as: CH2=CH-Cl. In line-bond structures, bonds and atoms are represented by lines and important atoms like Cl are labeled.

Verify the Structure

Count the number of bonds around each atom: C1 should have 3 sigma bonds and 1 pi bond (total 4 bonds), C2 should have 3 sigma bonds and 1 pi bond (total 4 bonds), Cl should have 1 bond (single sigma) attached to it, and hydrogens 1 bond each. This confirms that the structure satisfies the octet rule and matches the molecular formula.

Key concepts

Line-Bond Structure

In organic chemistry, a line-bond structure is a simplified way to represent molecules. It's an intuitive diagram that makes understanding complex molecules easier. Instead of drawing all individual atoms and their connections, each line represents a bond between atoms. In vinyl chloride, (CH₂=CHCl), the line-bond structure simplifies the visualization of how atoms are bonded.

• Each line represents a pair of shared electrons, or a bond. A single line stands for a single bond while a double line indicates a double bond.
• Carbon atoms are typically not labeled specifically unless necessary, as they are implied at the junctions of lines.
• Key atoms like chlorine are labeled to highlight their importance in the structure.

With vinyl chloride, depicting the double bond between carbon atoms in the line-bond structure captures the molecule's essential chemical behavior.
The vinyl group’s double bond (represented by = symbol) plays a major role in how the molecule reacts and its incorporation into larger compounds like PVC.

Alkene Chemistry

Alkenes are hydrocarbons with at least one carbon-carbon double bond. This double bond is what distinguishes alkenes from other types of hydrocarbons. The double bond in alkenes, such as in vinyl chloride, is a source of reactivity. In chemistry, this double bond makes alkenes reactive sites capable of undergoing various interesting chemical reactions.

• The double bond consists of one sigma (σ) bond and one pi (π) bond, providing different spatial arrangements and areas of electron density.
• This arrangement causes alkenes like vinyl chloride to have a planar structure, which can affect how they interact with other molecules.
• Alkenes are utilized as starting materials for producing diverse chemical products, owing to their versatile nature and reactivity.

The presence of a double bond makes alkenes valuable in synthetic chemistry, particularly in the creation of polymers and other complex materials. In the case of vinyl chloride, the double bond is crucial for forming polymers such as polyvinyl chloride (PVC).

Polyvinyl Chloride (PVC)

Polyvinyl Chloride (PVC) is a versatile plastic that is widely used in industry and everyday products. It is synthesized from vinyl chloride monomers through a process called polymerization. During this process, the double bonds in the vinyl chloride molecules open up and link together, forming chains of PVC.

• The polymerization transforms vinyl chloride from a reactive monomer to a stable plastic.
• PVC is known for its durability, resistance to environmental degradation, and versatility across different applications, from piping to clothing materials.
• Because of its chlorine content, PVC can exhibit fire-retarding properties, making it useful in safer building materials.

The transformation of vinyl chloride into PVC highlights the importance of understanding the chemical structure and behavior of the vinyl groups. Learning about PVC offers insight into how basic organic molecules can be manipulated into advanced materials with unique and valuable properties.