Question

How is a monosubstituted benzene named? Give the structures and names of two examples. Also give two examples of monosubstituted benzenes that have special names.

Short answer

A monosubstituted benzene is named by attaching the name of the substituent group to the word "benzene". For example, a benzene ring with a methyl group (-CH3) attached is called methylbenzene, and a benzene ring with a nitro group (-NO2) attached is called nitrobenzene. Some monosubstituted benzenes have special names, like phenol, which has a hydroxyl group (-OH) attached to the benzene ring, and aniline, which has an amino group (-NH2) attached.

Step-by-step solution

General Monosubstituted Benzene Examples

To provide general monosubstituted benzene examples, we will choose two substituent groups and attach them to the benzene ring, then name them using the IUPAC nomenclature. Example 1: Substituent: methyl group (-CH3) Structure: A benzene ring with a methyl group attached at one of the carbon atoms. Name: Methylbenzene Example 2: Substituent: nitro group (-NO2) Structure: A benzene ring with a nitro group attached at one of the carbon atoms. Name: Nitrobenzene

Monosubstituted Benzene Examples with Special Names

Now, we will provide two examples of monosubstituted benzenes that have special names. These compounds have specific common names that are widely understood and accepted, and don't follow the standard IUPAC nomenclature. Example 1: Substituent: hydroxyl group (-OH) Structure: A benzene ring with a hydroxyl group attached at one of the carbon atoms. Special Name: Phenol Example 2: Substituent: amino group (-NH2) Structure: A benzene ring with an amino group attached at one of the carbon atoms. Special Name: Aniline

Key concepts

IUPAC Nomenclature

IUPAC nomenclature is a universally accepted method for naming chemical compounds. This system helps chemists communicate without ambiguity. When it comes to monosubstituted benzene, the process involves naming the substituent attached to the benzene ring, followed by "benzene". For example:

• If a methyl group (-CH3) is attached, it becomes "Methylbenzene", commonly known as "Toluene".
• When a nitro group (-NO2) is attached, the compound is named "Nitrobenzene".

The IUPAC naming follows a straightforward procedure and is applicable to countless chemical compounds, ensuring consistent naming across various scientific communities. It serves as a universal language in chemistry, minimizing misunderstandings.

Phenol

Phenol is a monosubstituted benzene with a special name. It contains a hydroxyl group (-OH) attached to one of the carbon atoms on the benzene ring. Although it could be named hydroxybenzene, the term "Phenol" is widely used. This name originates from its historical discovery as a byproduct of coal tar distillation.
A few important properties and uses of phenol include:

• Phenol is known for its antiseptic properties, being used in medical applications.
• It's a precursor to many polymers and substances in pharmaceuticals.

Phenol is unique due to the polar nature of the hydroxyl group, which affects its interaction with water and other chemicals. Despite being toxic, it has significant roles in industry and research.

Aniline

Aniline is another example of a monosubstituted benzene with a special and recognized name. It consists of an amino group (-NH2) bonded to a benzene ring. While technically aminobenzene could be a proper IUPAC name, "Aniline" is the traditional and widespread name. This distinction is due to its early use in dye production.
Aniline holds several crucial attributes and applications:

• It is a fundamental substance in the manufacturing of dyes, specifically aniline dyes.
• Aniline plays a vital role in making plastics, rubber, and pharmaceuticals.

Owing to the amino group's presence, aniline shows unique chemical behavior, acting as a base in reactions. It's less polar than phenol and has different solubility patterns, which are essential when used in various chemical processes.

Chemical Structure

The chemical structure of monosubstituted benzene involves a benzene ring, which is a stable hydrocarbon structure with alternating double bonds, called aromaticity. When a single substituent is added to any of the carbon atoms on this ring, it forms a monosubstituted benzene compound.
Important characteristics of such structures include:

• The stability imparted by the aromatic ring, which resists reactions that would break the aromatic system.
• Reactivity directed by the substituent, influencing the site and type of further substitutions.

Understanding the chemical structure is crucial, as the position and type of substituent can significantly affect the compound's physical and chemical properties. In monosubstituted benzenes, each substituent alters the electronic distribution across the benzene ring, impacting its reactive nature with other chemicals.