Chemistry · General chemistry II · Worked example
Name a disubstituted benzene
A benzene ring carries a chlorine atom and an ethyl group, with one carbon between them. Name it.
Name the groups
The groups are chloro and ethyl.
Start numbering at the first group alphabetically
Chloro comes before ethyl, so the chlorine’s carbon is carbon 1. Counting the shorter way round, the ethyl group is at carbon 3.
Write the name
List the groups alphabetically with their numbers.
Result
1-chloro-3-ethylbenzene.
Your turn
Name a benzene ring with two chlorine atoms on opposite corners.
Show the answer and explanation
1,4-dichlorobenzene (p-dichlorobenzene).
Two identical groups, 1,4 apart: di- with both numbers, or para-.
Keep exploring
Set the target 1-ethyl-3-chlorobenzene on the drawing: it describes the structure, but numbering should start at the group first in the alphabet.
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