Name: Combustion: Burning of Substances
Uploaded: 2019-07-19
Duration: 9 min 40 s
Description: You may have seen a bonfire in the cold season, but do you know why the wood in the bonfire starts burning when we heat it? Let's explore.

Question

Explain the rules of IUPAC nomenclature with examples.

Accepted Answer

Rules for IUPAC Nomenclature are:

Select the longest continuous chain of carbon atoms known as parent chain. It may or may not be a straight chain.

The parent chain include ' $=$ ' or ' $\equiv$ ' bond along with the terminal functional groups.

The numbering starts from one end in such a way that the carbon atom involving multiple bonds gets the least possible number. For example,

${}^{5}{CH}_{3} -^{4} {CH}_{2} -^{3} CH =^{2} CH -^{1} {CH}_{3}$ (Correct numbering) ${}^{1}{CH}_{3} -^{2} {CH}_{2} -^{3} CH =^{4} CH -^{5} {CH}_{3}$ (Wrong numbering)

If a terminal functional group is present, the numbering of the chain must start from the carbon atom of the functional group. For example,

${}^{1}{CH}_{3} -^{2} {CH}_{2} -^{3} CHO$ (Wrong numbering)

${}^{3}{CH}_{3} -^{2} {CH}_{2} -^{1} CHO$ (Correct numbering)

The position of prefix is indicated by the numerical figures before the name and are separated by hyphen (-). Therefore, the IUPAC names of the above compounds are:

${}^{5}{CH}_{3} -^{4} {CH}_{2} -^{3} CH =^{2} CH -^{1} {CH}_{3}$ - Pent-2-ene.

${}^{3}{CH}_{3} -^{2} {CH}_{2} -^{1} CHO$ - Propanal (Propan-1-al)

Explain the rules of IUPAC nomenclature with examples.

Important Questions on Carbon and its Compounds

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