Question

The correct IUPAC name of the compound

is:

• A. 4-ethyl-1-fluoro-2-nitrobenzene
• B. 4-ethyl-1-fluoro-6-nitrobenzene
• C. 3-ethyl-6-fluoro-1-nitrobenzene
• D. 1-ethyl-4-fluoro-3-nitrobenzene

Answer 1

The Correct Option is A

IUPAC nomenclature of this compound proceeds as follows:

1. Parent chain identification: The parent chain is the benzene ring.
2. Substituent numbering: The substituents are ethyl, fluoro, and nitro. Numbering must assign the lowest possible locants. Prioritizing the nitro group alphabetically suggests locant 1. However, this yields locants 1, 4, and 5 for nitro, ethyl, and fluoro, respectively. Numbering from fluoro as locant 1 results in locants 1, 2, and 4 for fluoro, nitro, and ethyl, respectively, achieving a lower set of locants (1, 2, 4 vs. 1, 4, 5).
3. Alphabetical ordering of substituents: The substituents are ethyl, fluoro, and nitro.
4. Assembly of the name: The IUPAC name is 4-ethyl-1-fluoro-2-nitrobenzene.