There are four crucial properties that are displayed by the compounds of carbon. These are as follows:
- Combustion
- Oxidation
- Addition
- Substitution
What is Carbon?
Carbon is a chemical element that is non-metal that makes up about 0.025% of the earth’s crust. The various forms of carbon are diamond, graphite and graphene.
Physical Properties of carbon
- Elemental name: Carbon
- Symbol: C
- Atomic number: 6
- Group: 14
- Atomic weight: 12.011
- Crystal structure: Hexagonal
- Nature: Weakly acidic
- Physical state: Solid at room temperature
- Melting Point: 3550°C
- Boiling Point: 4827°C
Here in this article, we will discuss each one separately in detail.
Combustion Reaction
All the allotropic forms of carbon when burnt in the presence of oxygen releases carbon dioxide by giving off heat and light. Generally, most of the carbon compounds release a large quantity of heat and light when set to fire.
This can be said in a way that, the chemical reaction in which carbon or its compounds are burnt in presence of excess oxygen produce carbon dioxide with heat and light is known as combustion.
Consider some reactions to understand the same.
The burning of carbon in the presence of oxygen produces carbon dioxide and generate light with heat.
The burning of methane in the presence of oxygen generates carbon dioxide along with water, heat and light.
Ethanol when set to fire in the atmosphere produces carbon diode and water by giving off heat and light.
A point to be kept in mind over here is that the flame produced during the chemical reaction will depend on the type of carbon compound being burnt.
This means that in the case of saturated carbon compounds a clean bluish flame will be produced but for unsaturated carbon compounds, a yellow flame with black smoke will be given off. However, if saturated hydrocarbon is burnt with a limited supply of oxygen then the combustion will be incomplete and this will result in a yellow flame.
Oxidation Reaction
A reaction is said to be oxidation when the gain of oxygen by the substance takes place during the reaction. We have seen while discussing combustion that carbon or its compound are oxidized during combustion. Thus, we can say that combustion in a general basis, is an oxidation reaction but all oxidation reactions are not necessarily combustion reactions.
Consider the reaction given below:
In the above reaction, alkaline potassium permanganate is the oxidizing agent to the ethanol i.e., adding oxygen to it thereby generating acetic acid.
Addition Reaction
We know that when unsaturated hydrocarbons are added with more hydrogen atoms when catalysts like nickel are present then saturated hydrocarbons are produced.
You must note here that unsaturated hydrocarbons are the ones in which multiple covalent bonds (i.e., double or triple) exist between adjacent carbon atoms. These are generally alkenes or alkynes. Catalyst helps to vary the rate with which reaction is taking place without causing hindrance to the actual reaction.
Hydrogenation of vegetable oils in the presence of nickel is one of the major examples of the addition reaction.
Vegetable oils are considered healthy thus suit cooking because of the presence of long unsaturated chains of carbon which is not present in animal fats that have saturated fatty acids and are harmful to health.
Substitution Reaction
A reaction in which the replacement of an atom or group of atoms of a compound is replaced by another atoms or group of atoms is called a substitution reaction. Alkanes possess chemically unreactive and are inert with most of the reagents. But under suitable conditions, saturated hydrocarbons undergo some chemical changes which are known to be substitution reactions.
Consider the equation given below:
From the above reaction, it is clear that the reaction of methane with chlorine in the presence of sunlight gives methyl chloride with hydrogen chloride. Here it is shown that hydrogen atoms of CH4 are replaced by chlorine atoms.
