Chemical substances or compounds are classified into 2 types. Namely- mineral/ inorganic, organic. Inorganic compounds are obtained from rocks, soil, etc. They include minerals and ores. But, the organic compounds are obtained from animals and plants. The chemistry of organic/living compounds is called organic chemistry. Some common organic compounds are ethyl alcohol, acetic acid, urea, etc.

In the 18th century, organic compounds were obtained from natural sources. But, in modern days, we can prepare some organic compounds in the laboratory. Some common examples of organic compounds prepared in the lab are dyes, fertilisers, explosives, pesticides, drugs, perfumes, etc. This study material is helpful for students who want to gain a brief idea about organic chemistry.

What is organic chemistry? 

The chemistry of covalently bonded carbon compounds, except metallic carbides and oxide of carbons. The separate study material of organic compounds is needed because of a large number, typical behaviour, vast applications, and matter of convenience. Organic compounds contain carbon as main constituents along with O, N, S, P, halogens, a few metals, etc. These compounds have some characteristics like a covalent bond, insoluble in water, dissolve in organic solvents(ether, benzene), show molecular reactions, their solutions are non-conductors, show isomerism, etc.

Types of bonds:

A carbon atom can form different types of bonds with other carbon or other atoms in different organic compounds. Some chemical bonds are single bond, double bond, triple bond. A single bond between 2 carbon atoms is a sigma bond. A double bond consists of a strong sigma bond and a weak pi bond between 2 carbon atoms. This is also called an ethylenic bond. A triple bond consists of one sigma and 2 pi bonds between 2 carbon atoms. This is also called acetylenic linkage.

Hybridisation:

Depending on the number of half-filled atomic orbitals, hybridisation is of 3 different types. i.e. 

Tetrahedral hybridisation- Formation and structure of methane and ethane. 

Trigonal hybridisation- Structure of ethylene. 

Linear hybridisation- Formation of acetylene.

Classification of organic compounds:

 On the basis of the carbon skeleton, this is of two types.

1. Acyclic compounds- It consists of an open chain of carbon atoms. Example:- n-Butane, 2- Methyl propane, etc.

1. Cyclic compounds- It consists of closed chains or rings. It is further classified as :

• Alicyclic/ carbocyclic compounds- These ring compounds have a carbon atom at each corner of the ring. Examples- Cyclopropane, Cyclohexane, etc.
• Aromatic compounds- 2 or more rings can fuse. Examples- Benzene, Toluene, etc.
• Heterocyclic compounds- These ring compounds have one or more heteroatoms at the corner of the ring. 

Classification based on the functional group:

It may be a bond, an atom, or a group of atoms that is responsible for most of the physical and chemical properties of organic compounds. Some classes of organic compounds with their functional groups are listed below-

Isomerism:

When the same molecular formula represents 2 or more compounds that differ in their physical and chemical properties, then such compounds are called isomers. This phenomenon is called isomerism. Isomerism is of 2 types. i.e. Configurational and conformational. Configurational isomerism is of 2 types. i.e. Structural and stereoisomerism. Structural isomerism is of 6 types.

1. Chain isomerism- Butane, Pentane.
2. Position isomerism- 2- Methylpentane, 3- Methylpentane.
3. Functional isomerism- Ethanol, Dimethyl ether.
4. Ring-chain isomerism- Propene, Cyclopropane
5. Metamerism- Ethoxyethane, Methoxypropane.
6. Tautomerism- Methyl cyanide, Methyl isocyanide.

Uses of organic chemistry:

Organic compounds are around us. Many modern materials are partially composed of organic compounds. These are central to economic growth. Organic chemistry is foundational to the fields of biochemistry, biotechnology, and medicine. We can find organic compounds in agrichemicals, coatings, cosmetics, detergent, dyestuff, food, fuel, petrochemicals, pharmaceuticals, plastics, rubber, etc. Some uses of organic compounds are listed below-

1. Methane- Making motor tires, printing ink, production of light and energy, making methyl alcohol, formaldehyde, chloroform, etc.
2. Butane- Used as LPG fuel.
3. Ethylene- Fruit ripening, fruits preservation, in oxy-ethylene flame.
4. Acetylene- Producing light, in the form of Marcelin anaesthesia, in artificial ripening, etc.
5. Polythene- producing electrical resistance in wires and cables, in making layers in the cap of the bottle.
6. Ethyl bromide- Local anaesthesia.
7. Chloroform- In surgical operation as anaesthesia.
8. Methyl alcohol- Artificial colour, varnish, and polish.
9.  Ethyl alcohol- Making wine, varnish, and polish.
10. Glycerol- in ink of stamp, in shoes polish and cosmetics, in transparent soaps, etc.
11.  Formaldehyde- In making insecticides, waterproof cloths.
12.  Acetamide- In softening leather, cloth.
13.  Ethyl acetate- Medicines, artificial perfumes, etc.
14.  Urea- Fertiliser
15.  Oxalic acid- In colouration and printing cloth.
16.  Glucose- wine, preservation of fruits juices.
17.  Acetaldehyde- Sleeping pill, colour medicines.
18.  Acetone- synthetic rubber, sulphone, chlorine, chloroform, iodoform.

Conclusion

Organic compounds play an important role in the increase of economic growth. Organic chemistry is foundational to the field of biotechnology and pharmaceutical companies. We can find organic compounds in agrichemicals, coatings, cosmetics, detergent, dyestuff, etc. In modern times organic industrial chemistry focuses on converting raw materials into consumer and industrial products. Examples- natural gas, air, water, metals, oil, minerals, etc. Today, organic industrial chemistry is based crucially on petroleum and natural gas. Now, many industries focus on learning how to convert renewable resources into industrial organic chemicals.