Final answer:
In chemistry, compounds with substituents on a benzene ring are named using IUPAC naming conventions, assigning the lowest possible numbers for the substituents' positions and using prefixes for multiple substituents.
Step-by-step explanation:
In the field of chemistry, compounds with substituents attached to a benzene ring are named following specific conventions established by the International Union of Pure and Applied Chemistry (IUPAC). When naming such compounds, the benzene ring serves as the parent structure, and the substituents are named with precedence given to the one that provides the lowest numbering possible for the ring when assigning the location of other substituents.
For example, if a benzene ring has a methyl group and a nitro group attached, the compound could be named as methyl nitrobenzene, but the IUPAC name would be more precise. Using IUPAC rules, the specific positions of the substituents are denoted, resulting in names such as 1-methylnitrobenzene or 1-nitrotoluene, depending on which substituent is considered the primary functional group.
If there are multiple substituents, the benzene ring is named with prefixes like di-, tri-, etc., indicating the number of substituents, and the substituents themselves are listed in alphabetical order preceded by their respective positions on the benzene ring, e.g., 1,3-dinitrobenzene. When using common names for disubstituted benzene compounds, terms like ortho (o-), meta (m-), and para (p-) are used to describe the positions of the substituents relative to each other.