Reactions of Hydrocarbons english

Combustion, as we know means burning, such as burning of wood, burning of paper, burning of coal, etc.  

 in this we burn combustible materials, so that we can get heat and light.  And this heat and light we get due to the reaction with oxygen involved in it.  And the combustible material from which heat and light is obtained is called fuel.  These fuels are carbon or carbon compounds. When we talk about the combustion of Hydrocarbons, all the bonds present in the hydrocarbon are first broken, then combine with oxygen. This gives us CO2, H2O, Heat and light as a product.

For example:-

        

 

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As has been divided into hydrocarbons saturated (alkanes) and unsaturated (alkenes and alkynes). The percentage of carbon in saturated hydrocarbons is lower than that of unsaturated hydrocarbons. It burns completely, therefore giving white smoke and blue flame. Huh. While the combustion of unsaturated hydrocarbon gives black smoke and yellow flame, it also tests saturated and unsaturated hydrocarbons.

General formula of combustion for Alkanes -

Oxidation

Oxidation: - addition of oxygen is called oxidation, with which oxygen is added, its oxidation takes place. The substance that supplies oxygen is called an oxidant or oxidizing agent. This reaction is also a reaction of oxygen, but the combustion reaction breaks all bonds, and all omponents form different products with oxygen, whereas in oxidation, only carbon attached to the functional group forms bond with oxygen, such as: -

C₂H₅OH     CH₃COOH + H₂O

It can be understood in the form of an activity.

Procedure: -  Take 2-3ml ethanol (C₂H₅OH) in a beaker, add 5 ml NaOH to it, heat this solution slightly, now add acidified KMnO4 to this hot solution.

Observation: -  KMnO4 is of violet-pink color before being found. But its color vanish as soon as you get it, and it becomes colorless.

Conclusion: - The reason for the violet-pink color of KMnO4 is +7 oxidation state of Mn. Its +7 state is due to 4 oxygen atoms. If oxygen decreases then the oxidation state will be below +7 below the change, which will make it colorless. In this activity we see a clear that KMnO4 has become colorless, this means that the oxygen associated with Mn has decreased, Since oxygen has not been pumped out, it means that it must have been added to the ethanol of nickel from KMnO4. In this way, ethanol was converted to ethanoic acid.

Addition Reaction

Such reactions are carried out by alkene and alkynes. In this, there is a π bond break in C = C, and someone adds to the molecule from outside.

For example-

Convertion of oils into vanaspati ghee

Vegetation of oils causes hydrogen to change in Ghee, this hydrogenation is an addition reaction, in which metals like a catalyst of D-block like nickel / platinum / palladium etc. are used, in which   towads have hydrogen special affinity.

Let us see another example.

Convertion of ethene to 1,2 dibromo ethane

The color of bromine water is brownish-red, but when bromine water reacts with ethylene, bromine water de-colorizes, and a single product is found here. This means addition of Br₂. And this is an addition reaction.

Substitution Reaction

Substitution means replacement (replacing someone by someone else). Talking about hydrocarbons, there is a replacement of hydrogen attached to carbons. 

For example: -

In this reaction, hydrogen atom present in methane is replaced by chlorine atoms in the presence of sunlight. This is a substitution reaction. 

Elimination Reaction

The elimination of simple molecules like H2O, NH3, CH3OH, HCl from one of the big molecules is called elimination reaction. 

For example:-

Elimination reaction is opposite of combination reaction . In addition reaction  ethylene and acetylene used as a substrate use whereas in elimination reaction ethylene and acetylene are products.