Basic Concept of Organic Chemistry | Class 11 Chemistry Notes

Basic Concept of Organic Chemistry

Organic Chemistry:

The Branch of chemistry which deals with the organic compound is called Organic Chemistry.

Organic Compound:

Those compound which are obtained from living organism were called as organic compound. Example: Sugar, urea.

Or

Those compound which were developed from hydrocarbon and their derivative is called Organic compound.

Vital Force Theory:

Organic compounds can only be prepared or obtained by mysterious force existed in living beings". Accordingly, synthesis in lab was considered to be impossible.

In 1828 Friedrich Wohler made discovery which include the production of urea (organic compound) in the lab by heating ammonia and cyanic acid.

NH₃ + HCNO →NH₄CNO

NH₄CNO→CO(NH₂)₂

Note: First synthesized organic compound CH₃-COOH (Acetic acid by Kolbe).

Modern definition of organic compounds:-

"Hydrocarbons & their derivatives with covalently bonded carbon as essential element."

"Compounds of carbon except CO, CO₂, carbonates bicarbonates, carbides, some cyanides etc."

Organic Chemistry→ Study of chemistry of organic compounds.

Tetra-valency and Catenation Property of Carbon:

   i.            Tetravalencey: Carbon consists four valance electron in its outermost shell and shows tetravalencey. Carbon forms four covalent bonds by sharing valance electron is called tetravalencey of carbon.

 ii.            Catenation: Self-linking property exhibited by carbon to result long chain, branched chain & cyclic form, It is due to strong sharing tendency by its optimum electronegativity and smaller size.

Example: CH₃-CH₂-CH₂-CH₂-CH₂-CH₃

Classification of Organic Compound:

Aliphatic Hydrocarbon: The hydrocarbon which have straight chain carbon to carbon linkage is called aliphatic hydrocarbon.

   i.            Alkane: Hydrocarbon with single bond between carbons are called alkane.

Example: Methane (CH₃-CH₃)

 ii.            Alkene: Hydrocarbon with double bond between carbons are called alkane.

Example: Ethene (CH₂=CH₂)

iii.            Alkyne: Hydrocarbon with triple bond between carbons are called alkane.

Example: Ethyne (CH≡CH₂)

Cyclic or Closed chain Hydrocarbon: Those hydrocarbon in which carbon to carbon linkage is present in the form of circle or ring are called Cyclic or Closed chain Hydrocarbon.

i.                    Homo-cyclic Hydrocarbon: Those cyclic hydrocarbon in which ring atom are only carbon are called homo-cyclic hydrocarbon.

a.       Alicyclic: The cyclic organic compound which are similar to open chain compound in chemical behavior are called alicyclic or cyclic aliphatic organic compound.

Example: Cyclohexene

 

a.       Aromatic: Benzene and benzene like organic compounds are called aromatic compound.

Example: Phenol

i.                    Heterocyclic Compounds: The cyclic organic compounds which contains a skeleton of a cyclic ring containing at least a heteroatom in addition to carbon atom are called heterocyclic compound.

Example: Thiophene

Alkyl Group:

A group which is obtained by removing a hydrogen atom from alkane are called alkyl group.

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