If you do not understand hydrocarbons well, you might find it difficult to memorize! However, once you get a grasp of the topic, you will find it absolutely interesting! In this chapter, we will try to make this topic extremely interesting for you! Let us learn about the properties of aromatic hydrocarbons.
Based on the number and type of substitution of the ring the Aromatic compounds are named. Cyclic hydrocarbons with delocalized pi electrons between carbon atoms of the ring are defined as Aromatic Hydrocarbons. The phenomenon has aromatic nature that is called aromaticity. Benzene is the simplest aromatic compound. They are famous and well known for their strong, pungent aromas.
Structure of Benzene
Properties of Aromatic Hydrocarbons
- Properties of Aromatic Hydrocarbons include that their major sources are Petroleum and coal. They are well known for their exceptional physical and chemical properties. Poly-aromatic hydrocarbons are defined as aromatic compounds with more than one benzene. When they include in atmospheric pollution then it is known as carcinogenic in nature.
- Aromatic compounds also include amino acids and precursors to nucleotides. Which are soluble in water they are known as non-polar hydrocarbons. These hydrocarbons cannot form ions or H-bonds with water molecules. They are usually unreactive because of extra stability and for many organic and inorganic reactions it is widely used as an inert solvent.
- The ratio for carbon-hydrogen is high. They born with sooty yellow flame because of the presence of high carbon content.
- They go through electrophilic substitution reactions and nucleophile aromatic substitution.
- Hydrocarbons which have multiple bonds are unsaturated in nature like alkenes and alkynes. They tend to give addition reactions due to this unsaturation.
- Due to resonance and give characteristic electrophilic substitution reactions aromatic hydrocarbons are stable. The carbon ring acts as a nucleophile in these reactions and to form a substituted product an electrophile attack on benzene.
- With the coming electrophile, one of the H-atom of a ring is substituted because of this the product also holds its stability and aromatic in nature. On the opposite side in the addition reactions, aromatic compound may lose their aromaticity so they do not prefer to give such reactions.
Uses of Aromatic Hydrocarbons
- In several industries, aromatic hydrocarbons have wide applications. For example, for model glues, toluene is used as solvent while naphthalene is used as mothballs.
- For manufacturing of dyes, explosives, and drugs, Phenanthrene is an intermediate product which has a different synthetic process. Trinitrotoluene (TNT) or 2, 4, 6 trinitrotoluene is an important aromatic compound which is mainly used as explosive along with the preparation of explosive.
- 1, 2 benzenediols or pyrocatechol is advertised as catechol which is one of the most important components of a photographic developer.
Question For You
Q. What are the physical properties of Benzene?
Ans: In organic solvent benzene is soluble but it is immiscible in water. It is a colourless liquid. Benzene has a typical aromatic odour because it is an aromatic compound. It burns with sooty flame because it is highly inflammable.
Based on the positioning of double bond benzene shows the resonance that it can exist in different form. For this property benzene is stable. Benzene having density 0.87g cm-3 and it is lighter than water. It has a moderate boiling point that is 80.5oC and high melting point that is 5.5oC.