IUPAC Nomenclature of Alkanes, Alkenes and Alkynes

What is IUPAC Nomenclature?

A single chemical compound can have several acceptable systematic names and the systematic method of naming organic chemical compounds is called IUPAC Nomenclature but no two compounds can have the same.

Earlier, most of the compounds with the same structural formula were known by different names depending on the regions where they were synthesized. This naming system was very trivial since it raised a lot of confusion. Finally, a common naming system enlisting the standard rules was set up by IUPAC (International Union for Pure and Applied Chemistry) for the naming of compounds. This method of naming is known as IUPAC naming or IUPAC nomenclature. IUPAC nomenclature of alkanes, alkynes, and alkenes are explained below:

IUPAC Nomenclature

IUPAC Nomenclature of Alkanes, Alkenes, and Alkynes

Alkanes are the simplest hydrocarbons known to us. They have a general formula of CnH2n+2. Alkanes belong to the family of saturated hydrocarbons that is; they contain only sigma bond linkages between carbon and hydrogen. The organic compounds form a series, known as homologues series in which the successive compounds contain the same functional group and differ from one another by a β€˜β€“CH2’ group.

Alkenes and alkynes, on the other hand, are unsaturated hydrocarbons. In case of alkenes double bond linkages are seen and in alkynes, triple bond linkages are present. Rules underlying IUPAC nomenclature of alkanes, alkenes, and alkynes are discussed below:

  • The longest hydrocarbon chain is selected and is termed as parent chain in case of alkanes. In the case of alkenes and alkynes, hydrocarbon chain with double and triple bond is chosen as parent chain. Parent chain is named with the help of Greek alphabets such as hepta, octa etc.
  • For alkanes suffix β€˜-ane’ is used, for alkenes, suffix β€˜-ene’ is used and suffix β€˜yne’ is used for alkynes. For example, C2H6 is known as ethane, C2H4 is known as ethene and C2H2 is known as ethyne.
  • The parent chain is numbered such that we reach to the double-bonded or triple bonded carbon atom earliest. The position of the carbon atom with the double bond is mentioned in numerals. For example, CH3CH=CHCH2CH3 is named as Pent-2-ene.
  • In the case of multiple double bonds in the carbon chain, Greek numerical prefixes such as di, tri are used to denote their number.

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FAQs

1. What is meant by Iupac nomenclature?
Ans: IUPAC is an acronym for the International Union of Pure and Applied Chemistry, an internationally recognized body that has systematically named all chemical organic substances.

2. What is the full name of IUPAC?
Ans: A chemical nomenclature is a set of rules for the systematic generation of names of chemical compounds. The most widely used nomenclature in the world is the one produced and developed by the Pure and Applied Chemistry International Union (IUPAC).

3. Which is the simplest alkane?
Ans: The simplest alkane is methane.

4. How do you name an element?
Ans: The naming is easy for a two-element ionic compound. The name for the metal element is the first part of the name. The second part is the non-metal element name with the “-ide” suffix.

5. Is chloride a polyatomic ion?
Ans: There’s only one element in the regular ion, Chlorine. There are two elements in the polyatomic molecule, chlorine, and oxygen.

Detail discussion on Alkanes Physical Property

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