Carbon and Its Compounds: Carbon is an essential non-metal. The word ‘carbo’, which means ‘coal’ is derived from the Latin word. This is due to the fact that it is the primary component of coal. From fossil fuels to complex molecules, carbon is the most abundant chemical in most organic matter.

Bonding in Carbon

The atomic number of carbon is \(6\), which means that the electronic configuration of the atom of the carbon is \(2,\,4\). Since a carbon atom has \(4\) electrons in its outermost shell, it shares its outermost electrons and achieves the inert gas configuration. Therefore, the carbon atom forms covalent bonds.

Allotropes of Carbon

An element in different forms, having different physical properties but similar chemical properties is known as allotropes of that element. The three allotropes of carbon are:

i. Diamond,
ii. Graphite, and
iii. Buckminsterfullerene

Diamond	Graphite	Buckminsterfullerene
Diamond is a very heavy and exceptionally hard substance. It is the hardest natural substance known.	Graphite is an opaque greyish-black material. It has a soft, smooth feel to it and conducts electricity.	Buckminsterfullerene is an allotrope of carboncontaining clusters of \(60\) carbon atoms linked together to create spherical molecules.
It does not conduct electricity and can be produced artificially by exposing pure carbon to extreme pressure and heat.	In dry cells and electric arcs, graphite is used to make electrodes or graphite electrodes.	It has the formula \({\rm{C}} – 60\) and is a black solid at room temperature.
Diamonds are employed in a variety of cutting instruments, including glass cutters, marble saws, and rock drilling equipment.	Graphite helps in the formation of pencil cores (leads) and black paints.
Jewelry is made with diamonds.

Versatile Nature of Carbon

The unique nature of the carbon atom and its ability to form bonds with other atoms result in a huge number of organic molecules.

Carbon’s versatility can be understood through properties such as tetravalency and catenation.

i. Tetravalency

The valence shell of carbon has four electrons. Because it cannot gain or lose four electrons due to energy constraints, it makes covalent bonds with other elements to complete its octet. This explains its tetravalency as well as its capacity to produce a wide range of compounds.

ii. Catenation

Carbon has the unique ability to form larger molecules. Catenation is the self-linking property of carbon atoms with other carbon atoms to form long chains, rings, double or triple bonds.

Hydrocarbons

Carbon and Hydrogen combine together in different proportions to form a large number of compounds. These compounds are called hydrocarbons.

Types of Hydrocarbons

There are two types of hydrocarbons which are as follows-

1. Saturated hydrocarbon
2. Unsaturated hydrocarbon

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Saturated Hydrocarbons

The hydrocarbons in which the carbon atoms are connected only by single bonds are called saturated hydrocarbons.

They are also called paraffin or alkanes. They are represented by the general formula \({{\rm{C}}_{\rm{n}}}{{\rm{H}}_{2{\rm{n}} + 1}}\) Where n is the number of carbon atoms in a molecule of alkane. They are named by putting the suffix -ane.

Below given is a table of some saturated hydrocarbons-

Unsaturated Hydrocarbons

Hydrocarbons in which two carbon atoms in the molecule are joined by a double \(\left( = \right)\) or a triple \(\left( \equiv \right)\) bonds are called unsaturated hydrocarbons.

There are two types of unsaturated hydrocarbons- Alkenes and Alkynes

1. Alkenes

Unsaturated hydrocarbons that contain a double bond between the carbon atoms are called alkenes. They are represented by the general formula \({{\rm{C}}_{\rm{n}}}{{\rm{H}}_{2{\rm{n}}}}\) is the number of carbon atoms in a molecule, and its value starts from \(2\). They are named by putting a suffix as \( – {\rm{ene}}\).

Below given is a table of some alkenes-

2. Alkynes

Unsaturated hydrocarbons which contain triple bonds between two carbon atoms are called alkynes. They are represented by the general formula \({{\rm{C}}_{\rm{n}}}{{\rm{H}}_{2{\rm{n – 2}}}}\), where \({\rm{n}}\) is the number of carbon atoms, and its value starts from \(2\). They are named by putting the suffix as \( – {\rm{yne}}\).

Below given is the table of some alkynes-

Carbon Compounds on the Basis of their Structure

There are three structures possible for carbon compounds which are as follows-

i. Straight (unbranched) chain

ii. Branched

iii. Cyclic

Functional Groups

One or more hydrogen atoms are substituted by other atoms in a hydrocarbon chain based on their valencies. These are referred to as heteroatoms. Functional groups are heteroatoms or groups of heteroatoms that make a carbon compound reactive and determine its characteristics.

Homologous Series

A group of organic compounds that share the same functional group have similar chemical characteristics and differ by a \({\rm{C}}{{\rm{H}}_2}\) unit or \(14\) mass units.

Examples- \({\rm{C}}{{\rm{H}}_3}{\rm{OH}},\,{{\rm{C}}_2}{{\rm{H}}_5}{\rm{OH}},\,{{\rm{C}}_3}{{\rm{H}}_7}{\rm{OH}},\,{{\rm{C}}_4}{{\rm{H}}_9}{\rm{OH}}\)

Nomenclature of Carbon Compounds

The following steps are followed while naming a carbon compound-

1. Choose the carbon chain with the longest unbranched length.
2. Identify the functional group that is present.
3. Calculate the minimum position in the numbering of carbon atoms for the \({\rm{C}}\) atom that contains the functional group.
4. If the same substituent appears more than once, the location of each point where it appears is given, and the number of times the substituent groups are indicated by a prefix (di, tri, tetra, etc.).

Chemical Properties of Carbon Compounds

The reactions that carbon compounds go through are limited, despite the fact that there are millions of them. The following are some of the most important carbon compound reactions:

i. Combustion

Carbon compounds are generally used as a fuel because they burn in the presence of air to produce energy.

With enough air, saturated compounds (Alkanes) produce a clean blue flame; unsaturated compounds (Alkenes/Alkynes) produce a yellow sooty flame.

\({\rm{C}}{{\rm{H}}_4} + 2{{\rm{O}}_2} \to {\rm{C}}{{\rm{O}}_2} + 2{{\rm{H}}_2}{\rm{O}} + {\rm{heat}}\,{\rm{and}}\,{\rm{light}}\)
\({{\rm{C}}_2}{{\rm{H}}_5}{\rm{OH}} + 3{{\rm{O}}_2} \to 2{\rm{C}}{{\rm{O}}_2} + 3{{\rm{H}}_2}{\rm{O}} + {\rm{heat}}\,{\rm{and}}\,{\rm{light}}\)

ii. Oxidation

Carbon compounds like alcohols can be converted to carboxylic acid in the presence of oxidizing agents like alkaline \({\rm{KMn}}{{\rm{O}}_4}\).

iii. Addition Reaction

Only unsaturated compounds undergo an addition reaction in the presence of catalysts like nickel or palladium to convert into a saturated hydrocarbon.

This is used as a test to differentiate between a saturated and an unsaturated hydrocarbon. This is done by using bromine water. Unsaturated compounds will react with bromine water and will decolorize it, while saturated compounds will show no change.

iv. Substitution

Saturated compounds undergo a substitution reaction where an atom of Hydrogen or a group of atoms is replaced by another atom.

Some Important Properties of Carbon Compounds

Ethanol and ethanoic acid are two significant compounds that we encounter on a regular basis.

Ethanol

Physical properties

i. It’s a clear, combustible liquid with a pleasant aroma.
ii. Excellent solvent for drugs like iodine tincture as well as all alcoholic preparations.
iii. It is soluble in water.
iv. Absolute alcohol refers to pure ethanol.
v. Ethanol can cause drowsiness when consumed.

Chemical Properties

i. Molasses fermentation can be used to produce ethanol. Using microorganisms like yeast, the process includes the slow degradation of a complex organic substance like molasses into simpler chemicals like ethanol.
ii. Reaction with sodium- Ethanol easily interacts with sodium to produce sodium ethoxide and hydrogen gas.
\(2{\rm{Na}} + 2{{\rm{C}}_2}{{\rm{H}}_5}{\rm{OH}} \to 2{\rm{C}}{{\rm{H}}_3}{\rm{C}}{{\rm{H}}_2}{\rm{ONa}} + {{\rm{H}}_2}\)
iii. Dehydration- Ethanol is converted to ethene when heated to \(443\,{\rm{ K}}\) in the presence of highly concentrated sulphuric acid.

Ethanoic Acid

Physical Properties

i. Ethanoic acid \(\left( {{\rm{C}}{{\rm{H}}_3}{\rm{COOH}}} \right)\), often known as acetic acid, is a colourless liquid. It has the functional group carboxylic acid \( – {\rm{COOH}}\).
ii. It has a melting point of \(290\,{\rm{ K}}\).
iii. Water, ether, and ethyl alcohol are all miscible in it.
iv. Vinegar is a \(5 – 8\) percent acetic acid solution in water.
v. All carboxylic acids are weak acids that undergo partial ionisation.

Chemical Properties

i. Esterification- Ethanoic acid reacts with alcohols in the presence of concentrated sulphuric acid to form sweet-smelling compounds called esters.

ii. Ethanoic acid forms its salt and water when it combines with bases.
\({\rm{C}}{{\rm{H}}_3}{\rm{COOH}} + {\rm{NaOH}} \to {\rm{C}}{{\rm{H}}_3}{\rm{COONa}} + {{\rm{H}}_2}{\rm{O}}\)
iii. It forms its salt (sodium ethanoate, also known as sodium acetate) by reacting with carbonate and hydrogen-carbonate metal complexes and emitting carbon dioxide gas.

\({\rm{C}}{{\rm{H}}_3}{\rm{COOH}} + {\rm{NaHC}}{{\rm{O}}_3} \to {\rm{C}}{{\rm{H}}_3}{\rm{COONa}} + {{\rm{H}}_2}{\rm{O}} + {\rm{C}}{{\rm{O}}_2}\)
\(2{\rm{C}}{{\rm{H}}_3}{\rm{COOH}} + {\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_3} \to 2{\rm{C}}{{\rm{H}}_3}{\rm{COONa}} + {{\rm{H}}_2}{\rm{O}} + {\rm{C}}{{\rm{O}}_2}\)

Study Everything About Carbon

Soaps and Detergents

1. Soap is a sodium or potassium salt of fatty acids with a lengthy chain. They’re only useful in soft water.
2. Detergents are ammonium or sulphonate salts of long chain carboxylic acids. They work well in hard water.

A soap molecule has two ends- the Ionic or the hydrophilic part and the long hydrocarbon chain or the hydrophobic part.

Cleansing Action of Soap

A thin film of oil or grease holds dirt to the surface of an unclean cloth.

When a dirty cloth is soaked in soap or detergent solution, the soap or detergent nonpolar tail dissolves in the dirt, while the polar heads are held by the surrounding water. Detergent or soap micelles are generated with oily or greasy dirt at their centre (both greasy dirt and water attract soap or detergent).

The released oil particle is removed from the unclean surface and the cloth is cleaned when mechanically scrubbed or beaten on a stone or with a wooden paddle, or agitated in a washing machine. Detergents lower the surface tension of water to a greater amount than soap, resulting in a far more powerful cleansing action than soap.

Three Important Questions of Carbon and its Compounds

Q.1. Which organic compound is added to make ethanol unfit for drinking purposes? What is the name of the mixture formed?
Ans: Methanol which is highly poisonous, is added to make ethanol unfit for drinking purposes. The mixture is called methylated spirit or denatured alcohol.

Q.2. Why \({\rm{CHO}}\) group cannot be present in the middle of the carbon chain?
Ans: The \({\rm{CHO}}\) group is a terminal functional group since carbon has already been involved in three bonds and can only form one more. If it is in the middle, it must form two bonds, for a total of five bonds, which is not possible.

Q.3. Give a test that can be used to differentiate chemically between butter and cooking oil?
Ans: Butter is a saturated compound, and cooking oil is an unsaturated compound. Therefore, they can be chemically differentiated by using bromine water. It will be observed that cooking oil will decolorise the bromine water while butter will not.

Summary

FAQs on Carbon and its Compounds

Q1. What are carbon compounds?
Ans: Compounds with carbon atoms in their molecules are known as carbon compounds. They are chemical compounds in which a carbon atom is connected to another carbon atom or another element’s atom. The majority of these substances are organic in nature. They are further divided into two categories- saturated and unsaturated.

Q2. Why is carbon so important?
Ans: Carbon is a necessary component of all life on Earth. Carbon intake and outflow are a part of every plant and animal life, whether they take in carbon to help build food or release carbon as part of respiration. The importance of carbon seems to be immense- fossil fuels, polymers, soaps, detergents and most of the medicines we use are made up of carbon compounds.

Q3. What are the four types of carbon compounds?
Ans: Carbohydrates, lipids, proteins, and nucleic acid are the four major types of organic molecules found in all living things.

Q4. Which is the purest form of carbon?
Ans: Diamond is the purest form of carbon.

Q5. Why is carbon and its compounds kept in organic chemistry?
Ans: Organic chemistry is the study of the structure, characteristics, content, reactions, and synthesis of organic molecules that are carbon-based.  Organic compounds are carbon and hydrogen-based molecules that can contain a number of other elements.

Q6. Is carbon a compound?
Ans: Carbon is a non-metal with atomic number 6 and electronic configuration \(2,4.\) It is present in group \(14\left( {{\rm{IVA}}} \right)\) of the periodic table. Hence, carbon is not a compound it is an element. It forms a compound when it bonds with other atoms or groups of atoms.

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