What is Nomenclature Functional Groups?
Functional groups are the main structure of most organic compounds. The name of the organic compound depends on the functional group name and their bonding. That is why specific names of the functional groups are essential. Functional groups are named depending on their structure and properties. The main basis of naming functional groups is the number of carbon atoms and their position. There are some specific rules for nomenclature functional groups like other chemical compounds. Also, the nomenclature functional groups must follow the functional group priority order. There are some general functional groups, and almost all the organic compounds are under those functional group categories.
What is Organic Compound?
Organic compounds are a type of chemical compound formed with carbon atoms. These compounds are formed by one or more covalent bonding between carbon and other atoms. Also, organic compounds include carbon and hydrogen bonds. Carbon atoms are the main element of an organic compound because carbon has catenation properties. There is a huge number of organic compounds in chemistry. Almost all carbon compounds form organic compounds. But some carbon compounds cannot form organic compounds, such as cyanide salts, carbonate anion salts, and carbon dioxide. Difficult pure forms of carbon called allotropes are also organic compounds. Many organic compounds have different functional groups in their structure.
What is a Functional Group?
An individual atom or a compound that is formed uniquely is called a functional group. It is also the most reactive part of an organic molecule. The compounds which have the same functional group cause the same type of reaction. Like C₂H₅OH (ethanol) and C₃H₇OH (propanol), both cause the same type of reactions as both of the compounds to have the same functional group, that is, OH. Both liberate hydrogen when the compound is treated with sodium metal. While naming an organic compound containing a functional group, naming functional groups, we have to follow the priority order in IUPAC nomenclature.
Priority Order of Functional Groups in IUPAC Nomenclature
When a molecule has multiple functional groups attached to it, we need to follow the priority order of functional groups in IUPAC nomenclature for naming functional groups. According to the table, starting from the functional groups having the highest priority are:
Carboxylic acid (prefix: carboxy-, suffix: -carboxylic acid or -oic acid) example: ethanoic acid
Sulfonic acid (prefix: sulfo-, suffix: -sulfonic acid) example: benzenesulfonic acid
Ester (prefix: alkoxycarbonyl-, suffix: -oate) example: methyl ethanoate
Acid halide (prefix: halo carbonyl-, suffix: -oyl halide) example: ethanoyl chloride
Amide (prefix: carbamoyl-, suffix: -carboxamide or -amide) example: ethanamide
Nitrile (prefix: cyano-, suffix: -nitrile) example: ethanenitrile
Aldehyde (prefix: formyl-, suffix: -al or carbaldehyde) example: ethanal
Ketone (prefix: oxo-, suffix: -one) example: 2-propanone
Alcohol (prefix: hydroxy-, suffix: -ol) example: methanol
Thiol (prefix: mercapto-, suffix: -thiol) example: methanethiol
Amine (prefix: amino-, suffix: -amine) example: methylamine
(Image will be Uploaded Soon)
Steps For Nomenclature Functional Groups
There are some specific steps for the nomenclature of organic compounds. The naming rules of functional groups should also follow those steps. The general steps are-
At first, the longest carbon chain is to be determined.
All the substituents from parent chains are to be identified.
The functional group of the compound is to be identified next.
Determine the number of carbon compounds and carbon-hydrogen bonds.
At the last step, the functional group will be named considering the above factors and following the IUPAC nomenclature rules.
Solved Examples
1.Mention the Functional Group Name of these Organic Compounds: CH₃Br, CH₃NH₂, CH₃CH₂OH, CH₃OCH₃.
Solution:
CH₃Br (methyl bromide) - Alkyl halide
CH₃NH₂ (methyl amine) - Amine
CH₃CH₂OH (ethanol) - Alcohol
CH₃OCH₃ (dimethyl ether) - Ether
2.Mention the Classification Process of the Functional Group.
Solution: There can be one or more carbon compounds and carbon-hydrogen bonds. The number of carbons detects the functional groups. The first carbon is known as alpha carbon, which is attached to the functional group. Following the same method, the second and third carbon is called beta and gamma carbon, and so on.
3.Mention the Priority List of Functional Groups.
Solution: The priority of functional groups in IUPAC nomenclature is -COOH > -SO3H > -COOR > -COCl > -CONH₂ > -CN > HC=O > -CO > -OH > -NH₂ > C=C > C-C.
FAQs on Nomenclature Functional Groups
1.How Many Common Functional Groups are there in Organic Chemistry?
Organic chemistry is a vital and huge part of chemistry. The main element of an organic compound is carbon atoms. Depending on the carbon bond structures and arrangements, the different carbon bondings and positionings are called functional groups. One or more functional groups form every organic compound. The functional groups have individual names based on their carbon atoms and bond structures. There are nine common functional groups in organic chemistry. All the common groups are named following the IUPAC nomenclature rules and priority order of functional groups in IUPAC nomenclature. The common functional groups of organic chemistry are aldehyde, amine, hydroxyl, ketone, phenyl, amino, ether, amide, ester.
2.Mention the Basic Principles of IUPAC Naming.
IUPAC nomenclature is a general naming process for all organic compounds. IUPAC names of organic compounds are necessary to avoid long names of the compounds. Also, IUPAC names should be convenient for identification. Considering all these factors, the basic principles of IUPAC naming and are The parent hydrocarbon chain should have maximum branches, maximum substituents, maximum length, maximum single, and multiple bonds. The parent functional group should have the highest order of precedence. The side chains of organic compounds, which are not present in the parent chain, should be determined correctly. The numbering of chains and bonds should follow the priority order.
3.Explain these functional groups in depth.
(i) Ketone
(ii) Aldehyde
(iii) Ester
(iv) Carboxylic acid
Ketone :
This compound has oxygen in bond with carbon atoms. This carbon is also bonded to two or more carbon atoms.
This can be named using the IUPAC system or common system as well.
Ethyl methyl ketone, phenyl propyl ketone, phenyl p-tolyl ketone are some examples of compounds that are named using the IUPAC system.
Some aromatic chains like acetophenone, benzophenone get their common names in the IUPAC system.
In the human body, ketone is also produced in the liver and has a complex structure which reacts with hundreds of other enzyme structures further.
(ii) Aldehyde -
It is an organic compound having C(H)=O in it's structural formula.
They are also known as formal groups and are very common in daily life.
They are also used in the technology and biological spheres.
Acyclic aliphatic aldehydes are the aldehydes which have the longest carbon chain and contain the aldehyde group.
If the CHO group is attached to a ring -carbaldehyde is used as the suffix while naming a compound. Due to this, C6 H11 CHO is named as cyclohexanecarbaldehyde.
(iii) Ester
The chemical compound ester is derived from an acid (organic or inorganic) –OH hydroxyl group is replaced by an –O– alkoxy alkyl group.
This is also seen between carboxylic acid and alcohol undergoing a substitution reaction.
These compounds have a sweet and pleasant smell and are commonly used in making deodorants and perfumes etc.
These are also used to make synthetic lubricants and polyester are very commonly used in making plastic bags and packets.
They are harmful for the environment because they can leave toxic effects when not being decomposed properly.
They can be prepared by the process of Esterification which is a chemical reaction between two reactants.
(iv) carboxylic acid -
The organic which contains carboxyl group i.e (C(=O)OH) attached to the -R is called carboxylic acid.
R−COOH and R−CO2H are some general carboxylic acids where R refers to the alkyl group, alkenyl group, aryl group etc.
The amino acids and fatty acids are very common examples of carboxylic acid.
These are polar and also practice hydrogen bonding.
The carboxylic acids which are smaller in structure are soluble in water whereas bigger ones are hardly soluble.
These have higher boiling point than water due to the greater surface areas and are Brønsted–Lowry acids.
4.Explain the purpose of the nomenclature system in brief?
The need of nomenclature is because it helps in establishing an international standard of naming compounds. This also provided better classification of compounds on the basis of name and structures. The IUPAC structural naming facilitates scientific naming and provides unique and unambiguous names to every compound. This means that each chemical name should refer to a single substance and has a different name on the basis of its structure.
Similarly, students can learn more about different topics related to courses like NEET, JEE and other competitive exams. Vedantu provides free of cost study materials that include notes, PDF files and series of questions to all students. Also, MCQ are also available (according to the latest pattern of exams) on the vedantu website to prepare for mcq based exams as well.
5.Give the answers to the following MCQs :
A) CH3 [CH2]18 CH3 is the formula for which of the following?
icosane
henicosane
docosane
tricosane
Ans: a) icosane
B) CH3 [CH2]19CH3 is the formula for which of the following?
icosane
henicosane
docosane
tricosane
Ans: b) henicosane
C) CH3 [CH2] 20CH3 is the formula for which of the following?
icosane
heneicosane
docosane
tricosane
Ans: c) docosane
D) CH3 [CH2] 21CH3 is the formula for which of the following?
icosane
henicosane
docosane
tricosane
Ans: d) tricosane.
E) CH3 [CH2] 6 CH3 is the formula for which of the following?
octane
nonane
decane
undecane
Ans: a) octane
F) CH3 [CH2] 7 CH3 is the formula for which of the following?
octane
nonane
decane
undecane
Ans: nonane
G) CH3 [CH2] 8 CH3 is the formula for which of the following?
octane
nonane
decane
undecane
Ans: c) decane
H) CH3 [CH2] 9 CH3 is the formula for which of the following?
octane
nonane
decane
undecane
Ans: d) undecane
I) CH3 [CH2] 2 CH3 is the formula for which of the following?
octane
nonane
butane
none of the above
Ans: c) butane
J) CH3 [CH2] 3 CH3 is the formula for which of the following?
octane
nonane
pentane
none of the above
Ans: c) pentane
