Alkanes, its Characteristics, Sources & Representation

Alkanes

such saturated hydrocarbons where all four valancies are satisfied by single covalent bond and has no capacity to add further atoms in its chain is called alkanes. Exampls are methane, propane, butane and octane etc.

Characteristics or properties of alkanes

It is as follow

It is called saturated hydrocarbons as it valency is satisfied by single covalent bond.
Its formula is Cn H2n + 2. Where n is number of carbon atoms.
It ends with suffix ane.
It is not soluble in polar solvent but is soluble in non-polar solvents.
It is non-polar in character.
It is inert compounds. So do not react easily.
It reacts at extreme condition.
During reaction alkanes go under oxidation and producing a lot of heat and energy.
It is also used as a lubricating oil and fuel.
It is also used in making of valuable products.

Sources of alkanes

As we know that millions of years ago, due to the geographical changes the plants and to some extent animals were buried under the earth. After the passage of time the higher temperature and pressure inside the earth covert the buried animals and plants into the organic compounds. These are coal, petroleum and the natural gas (Methane) etc. so the alkanes are obtained from natural gas, petroleum or crude oil when these are present in varing composition mixture by the process of fractional distillation which is carried in oil refiners.

Structure of alkanes

it structure is represented in two ways.

Line representation
Dot and cross representation

Line representation

such structure which is represented by straight lines which shows bonds and angle of bond is called line representation.

Lewis structure or dot and cross representation

Such structure which shows sharing of electrons b/w atoms of the molecule by dot and cross is called Lewis structure or dot and cross structure.

Angle b/w H–C–H of alkanes

the angle b/w H–C–H is 109.5 degree and thus a regular tetrahedron structure is achieved.

Bond length b/w C–C of alkanes

the bond length b/w C–C is 1.54 Angstrom which is equal to 154 pm.

Bond length b/w C–H of alkanes

the bond length b/w C–H is 1.10 angstrom which is equal to 110 pm.

Angstrom

A unit of length equal to one hundred-millionth of a centimetre that is 10⁻¹⁰ metre is called angstrom. It is used mainly to express wavelengths and interatomic distances. One angstrom is equal to 10⁻¹⁰ metre and 1pm is equal to 10⁻⁹ metre

Onllogy is on at

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14 February 2015