Choose the correct IUPAC name of the following compound:

The correct answer is Option (2) → 4-Fluoro-3-methylpent-2-ene

For an alkene, the IUPAC name is built on the longest chain that contains the C=C bond. The chain is numbered from the end that gives the double bond the lowest locant, and the substituent prefixes are written in alphabetical order.

The structure is:

    \( \displaystyle \ce{CH3-CH=C(CH3)-CH(F)-CH3} \)

• The longest chain through the double bond has five carbon atoms: pentene.

• Numbering from the left, the double bond starts at C2 (from the right it would start at C3), so the parent is pent-2-ene.

• With this numbering the methyl group is on C3 and the fluorine on C4.

• Alphabetical order: fluoro (f) before methyl (m).

So the name is 4-fluoro-3-methylpent-2-ene.