Question

What are Hydro-carbons? Write the name and general formula of
a. Saturated Hydro-carbons
b. Unsaturated Hydro-carbons
And, draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated?

Answer 1

Hint:
1. The general formula of Unsaturated hydrocarbons is: \[{C_n}{H_{2n}}\] or \[{C_n}{H_{2n - 2}}\]
2. The general expression for saturated hydrocarbons is: \[{C_2}{H_{2n + 2}}\]
3. As the number of Hydrogen in saturated hydrocarbons is more than the number of Hydrogen present in Saturated hydrocarbons, so, after addition of extra Hydrogen atoms unsaturated can be converted into saturated one.

Complete answer:
As the name suggests, hydrocarbons are nothing but a compound which are formed by Hydrogen and Carbon.
The general formula of hydrocarbon is, \[{C_x}{H_y}\] where, C is carbon while H is Hydrogen, while values of x and y are 0, 1, 2, ….
On the basis of presence of Hydrogen and Carbons, Hydro-carbon can be mainly divided into two categories:
1. Saturated hydrocarbons: Saturated hydrocarbons are that type of hydrocarbon in which the number of Hydrogen is two more than the twice the number of Carbon atoms. Here, Carbon-carbon atoms and Carbon-Hydrogen atoms are closed together by a single bond. They are compact in nature. The general expression for such hydrocarbons is: \[{C_2}{H_{2n + 2}}\].
2. Unsaturated hydrocarbons: Unsaturated hydrocarbons are that type of hydrocarbons in which there is presence of single, double and triple bond between the Carbon-Carbon atoms. The general examples of such hydrocarbons is: \[{C_n}{H_{2n}}\] or \[{C_n}{H_{2n - 2}}\].
So from the above statements we can easily conclude that, in saturated hydrocarbons the number of Hydrogen is more as in compared to unsaturated hydrocarbons.
So, if we add Hydrogen to the unsaturated hydrocarbons, then the added Hydrogen can easily break the C-C bond, and we will easily get saturated hydrocarbons.
Let us take an example,
\[C{H_2} = C{H_2} + {H_2}\xrightarrow{{Ni}}C{H_3} + C{H_3}\]
Unsaturated hydrocarbons are easily converted into saturated hydrocarbons after addition of Hydrogen atoms.These reactions are called hydrogenation reactions.

Additional Information:
Unsaturated hydrocarbons are basically of two types:
1. Alkene: The general representation of such hydrocarbons is \[{C_n}{H_{2n}}\] i.e. here in such hydrocarbon the number of carbon atom is half as the number of Hydrogen atoms.
2. Alkyne: The general representation of such hydrocarbons is \[{C_n}{H_{2n - 2}}\], i.e. here in such hydrocarbon the number of carbon atoms two less than the twice as number of Hydrogen atoms.

Note:
1. Alkene and Alkyne are two different types of Unsaturated Hydrocarbons.
2. The additions of Hydrogen help the unsaturated Hydrocarbons in breaking of single, double or triple C-C bonding and due to that there is formation of C-H bonding.