Hydrocarbons

Classification of Hydrocarbons

Hydrocarbons are broadly classified into aliphatic (acyclic) and cyclic compounds. Aliphatic hydrocarbons include saturated alkanes and unsaturated alkenes and alkynes, while cyclic hydrocarbons include alicyclic and aromatic compounds like benzene.

Conformations of Alkanes

Alkanes exhibit different spatial arrangements called conformations due to free rotation around carbon-carbon single bonds. Ethane specifically shows staggered and eclipsed conformations, where the staggered form is more stable due to minimal torsional strain.

Markovnikov's Rule

During the electrophilic addition of an unsymmetrical reagent to an unsymmetrical alkene, the negative part of the addendum attaches itself to the carbon atom possessing lesser number of hydrogen atoms.

Geometrical Isomerism

Alkenes show cis-trans isomerism due to the restricted rotation around the carbon-carbon double bond. Cis isomers have similar groups on the same side, while trans isomers have them on opposite sides.

Aromaticity and Huckel's Rule

Aromatic compounds are cyclic, planar systems that follow Huckel's Rule, possessing (4n + 2) pi electrons where n is an integer (0, 1, 2, ...), imparting exceptional stability to the ring like in benzene.

Directive Influence of Functional Groups

In electrophilic aromatic substitution of monosubstituted benzenes, existing groups dictate whether the incoming group occupies the ortho, meta, or para position based on their activating or deactivating nature.