What are Hydrocarbons and its types? NCERT Chemistry Class 11

What are Hydrocarbons and its types? NCERT Chemistry Class 11

Organic chemistry is all about reactions, structures and properties(whether physical or chemical properties) of an organic compound containing carbon atoms along with covalent bonds(a chemical bond which involves sharing of electrons between atoms).

Hydrocarbons

Hydrocarbons, as the name suggests, is a combination of two words and they are hydro stands for hydrogen and carbons which implies that it contains only two elements which are hydrogen and carbon.
Let’s take a look over on the definition of these two elements to get a clear concept of the hydrocarbons.

i. Carbon is a chemical element with a symbol C, it has atomic number 6, it is nonmetallic and tetravalent as there are four electrons available to form covalent chemical bonds.

ii. Hydrogen is the lightest element in the periodic table with the symbol H, atomic number 1 and molecular formula H with a base of 2, it readily forms covalent compounds with most non-metallic elements.

Hydrocarbons are entirely made of up carbon and hydrogen. In hydrocarbons, one or more carbon atoms bond together along with hydrogen composition to make organic compounds. Hydrocarbons are the principal constituents of petroleum and natural gas. They are also used in the manufacture of polymers like polythene, polypropene, etc. Hydrocarbons play an important role in our daily life as it is a constituent of fuels, natural gas, dyes, drugs and many more.

Even the individual hydrocarbon consists of large parts with chemical bonds that link together the atoms of their constituent molecules. In the 19th century hydrocarbons are classified into either aliphatic (hydrocarbons derived from chemical degradation of fats)or aromatic(hydrocarbons derived from chemical degradation of pleasant-smelling plants).

Read other chemistry notes for class 11 Uses of HYDROGEN, Preparation, and Properties

TYPES OF HYDROCARBONS

Based on types of carbon-carbon bonds, they are of three types-

i. Saturated Hydrocarbons
Saturated hydrocarbons contain carbon-carbon and carbon-hydrogen single bonds. Alkanes are also saturated hydrocarbons.

ii. Unsaturated Hydrocarbons
Unsaturated Hydrocarbons contain carbon-carbon double bonds or triple bonds or both.

iii. Aromatic Hydrocarbons
Aromatic hydrocarbons are special types of cyclic compound.

The two main types of Hydrocarbons are

1. Aliphatic hydrocarbons
2. Aromatic hydrocarbons.

ALIPHATIC HYDROCARBONS
Aliphatic hydrocarbons are classified into three main groups according to types of bond and they are:

i. ALKANES

ii. ALKENES

iii. ALKYNES

ALKANES

a). Alkanes are saturated open-chain hydrocarbons contains carbon-carbon single bonds.

b). Alkanes only contain hydrogen and carbons atoms, in which all the carbon-carbon bonds are single.

c). Alkanes are the least reactive hydrocarbon species.

d). Alkanes do not contain a double or triple bond between carbon-carbon atoms.

e). Alkanes have general formula C(_n)H_(2n+2) where n and 2n+2 are in the base of C and H respectively.

f). Alkanes are further divided into linear straight-chain alkanes, branched alkanes and cycloalkanes.

g). A most common example of alkanes is Methane (CH₄) and Ethane(C₂H₆).

ALKENES

a). Alkenes are unsaturated hydrocarbon which contains at least one double bond between two carbon atoms.

b). Alkenes contain at least two sp2 hybridized carbon atoms along with hydrogen atoms.

c). Alkenes have general formula C_(n)H_(2n) where n and 2n are in the base of C and H respectively.

d). Alkenes are also known as olefins which mean oil forming.

e). The physical state of alkenes is depended on the carbon atoms they contain.

f). Alkenes are very important chemical compounds as they are used for the manufacture of polymers like Polyvinyl Chloride (PVC) and polystyrene.

g). Most common examples of alkenes are Ethene (C₂H₄) and Propene(C₃H₆).

ALKYNES

a). Alkynes are also unsaturated hydrocarbons which contain at least one triple bond between two carbon atoms.

b). The general formula of alkynes is C_(n)H_(2n-2) where n and 2n-2 are in the base of C and H respectively.

c). Alkynes have fewer hydrogen atoms as compared to alkanes and alkenes.

d). Generally, Alkynes are present in gaseous form.

e). Alkynes are soluble in an organic compound and insoluble in water.

f). Alkynes are more acidic than alkanes and alkenes.

g). The boiling point of alkynes is also higher than alkanes and alkenes.

h). A most common example of alkynes is acetylene which is used for arc welding purpose.

AROMATIC HYDROCARBONS

Aromatic Hydrocarbons are also known as Arenes. Aromatic Hydrocarbons are those hydrocarbons which posses special stability. Most of these hydrocarbons contain a benzene ring. The most common aromatic hydrocarbon is benzene. The term aromatic is coined because of the sweet and pleasant smell of the compounds. Aromatic hydrocarbons are a constituent of coal and petroleum though it is more common in coal. Some of the aromatic compounds are toxic like benzene.

Though we can say that Hydrocarbons are made of nothing more than carbon and hydrogen atoms. They are insoluble in water and they attach themselves with different groups to make molecules.