Hydrocarbon: chemistry

An Introduction

There are about more than 10 million organic compounds and estimated to getting discovered many more upto the astronomically high number.

The credit goes to the special characteristics "catenation" and "tetravalency" of carbon atom which make carbon able to form so huge number of compounds.

HYDROCARBONS are simplest Organic Compounds and contain carbon and hydrogen only as constituent atoms.

The word "Hydrocarbon" is the combination of two words, i.e. "Hydro" from hydrogen and "Carbon".

Similarly, molecules of "Hydrocarbon" are the result of combination of hydrogen and carbon molecules only.

Hydrogen + Carbon = Hydro + Carbon = Hydrocarbon

Thus, Hydrocarbons are organic compounds composed of hydrogen and carbon only. Or Organic compounds made of hydrogen and carbon atoms only are called Hydrocarbons.

Example

Methane (CH₄), Ethane (C₂H₆), Acetylene(C₂H₂), Ehtylene (C₂H₄), Pentyne, Pentene, etc.

Classification of Hydrocarbon

On the basis of saturation of hydrogen atoms and type of bonds present, hydrocarbons can be divided into two groups

(A) Saturated Hydrocarbons

(B) Unsaturated Hydrocarbons

(A) Saturated Hydrocarbon

Hydrocarbons, whose molecules are joined by single bonds and no more hydrogen atom can be added further, are called Saturated Hydrocarbons.

Saturated hydrocarbons mean saturated with hydrogen atoms.

Saturated Hydrocarbons are known as Alkanes also.

Alkanes or Saturated Hydrocarbons are known as Paraffins.

General Formula of Saturated Hydrocarbons (Alkanes)

The general formula of saturated hydrocarbons, i.e. alkanes is

= C _n H _(2n+2)

Where n is the number of carbon atoms and can be equal to 1, 2, 3, 4, . . . .

(1) When `n = 1` i.e. number of carbon atoms = 1

Therefore, C _n H _2n+2

= C₁H_(2×1+2)

= C ₁ H ₄

Or, C H ₄

C H ₄ is the first member of Saturated hydrocarbon i.e. Alkane. And its name is Methane

The structural formula of Methane (C H ₄) is

(2) When `n = 2` i.e. number of carbon atoms = 2

Therefore, C _n H _{2 n + 2}

= C ₂ H _{(2 × 2 + 2)}

= C ₂ H ₆

C ₂ H ₆ is the second member of Saturated hydrocarbon i.e. Alkane. And its name is Ethane

The structural formula of Ethane (C ₂ H ₆) is

(3) When `n = 3` i.e. number of carbon atoms = 3

Therefore, C _n H _2n+2

= C ₃ H _{(2 × 3 + 2)}

= C ₃ H ₈

And its name of alkane having three carbon atoms is Propane

The structural formula of Propane (C₃H₈) is

(4) When `n = 4` i.e. number of carbon atoms = 4

Therefore, C _n H _2n+2

= C ₄ H _{(2 × 4 + 2)}

= C ₄ H ₁₀

And the name of alkane having four carbon atoms is Butane

The structural formula of Butane (C₄H₁₀) is

(5) When `n = 5` i.e. number of carbon atoms = 5

Therefore, C _n H _2n+2

= C ₅ H _{(2 × 5 + 2)}

= C ₅ H ₁₂

And the name of alkane having five carbon atoms is Pentane

The structural formula of Pentane (C₅H₁₂) is

(6) When `n = 6` i.e. number of carbon atoms = 6

Therefore, C _n H _2n+2

= C ₆ H _{(2 × 6 + 2)}

= C ₆ H ₁₄

And the name of alkane having six carbon atoms is Hexane

The structural formula of Hexane (C₆H₁₄) is

(7) When `n = 7` i.e. number of carbon atoms = 7

Therefore, C _n H _2n+2

= C ₇ H _{(2 × 7 + 2)}

= C ₇ H ₁₆

And the name of alkane having seven carbon atoms is Heptane

The structural formula of Heptane (C₇H₁₆) is

(8) When `n = 8` i.e. number of carbon atoms = 8

Therefore, C _n H _2n+2

= C ₈ H _{(2 × 8 + 2)}

= C ₈ H ₁₈

And the name of alkane having Eight carbon atoms is Octane

The structural formula of Octane (C₈H₁₈) is

(9) When `n = 9` i.e. number of carbon atoms = 9

Therefore, C _n H _2n+2

= C ₉ H _{(2 × 9 + 2)}

= C ₉ H ₂₀

And the name of alkane having Nine carbon atoms is Nonane

The structural formula of Nonane (C₉H₂₀) is

(10) When `n = 10` i.e. number of carbon atoms = 10

Therefore, C _n H _2n+2

= C ₁₀ H _{(2 × 10 + 2)}

= C ₁₀ H ₂₂

And the name of alkane having Ten carbon atoms is Decane

The structural formula of Decane (C₁₀H₂₂) is

Saturated Hydrocarbons having cyclic structure are called saturated cyclic hydrocarbons. And those having open chain structure are called Acyclic saturated Hydrocarbons.

Example of some cyclic saturated hydrocaronbs

Cyclopentane (C₅H₁₀)

Or,

Or,

Cyclohexane (C₆H₁₂)

Or

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