Q39 of 40 Page 84

Write the rules used in nomenclature of alkane.

The rules used in nomenclature of alkanes are:

Select the longest straight chain of carbon atoms in the molecular structure - this gives the parent name of the compound.


● Recognize any substituent on the longest chain. There are usually the following alkyl substituents:



Number the carbon atoms on the straight chain, such that those bearing the substituent would have the lowest number.


● If there are two or more same substituent, use the prefixes: di- for two; tri-for three and tetra- for four, before the name of the substituent.


● If there are two substituents on the same carbon, then the position of that carbon is indicated twice before the names of the substituents.


● Write the names of the compound as one word, separate numbers from substituents groups and prefixes with a hyphen and numbers from each other with a comma .


● The position of carbon bearing the substituents is written first, followed by prefixes, then the name of substituents in alphabetical order, then finally the parent name.


More from this chapter

All 40 →