3.2.5—IUPAC nomenclature

Step	Naming decision
1	Choose the longest parent chain
2	Number to give the relevant feature the lowest locant
3	Identify unsaturation and functional group
4	Assemble prefixes, locants, and suffix

Apply the systematic sequence to saturated or mono-unsaturated compounds with up to six carbons and one functional-group type.

For CH₃CH(OH)CH(CH₃)CH₃, choose the four-carbon chain containing –OH, number from the end that gives –OH the lower locant, and name 3-methylbutan-2-ol. The principal suffix controls numbering before a substituent does; check locants, punctuation and retained unsaturation at the end.

Representative question

[Maximum number: 1]

Deduce the systematic name of X using IUPAC nomenclature.

Retrieve the route: translate formulae, identify functional groups and series, name and classify isomers, then use mass, IR, and NMR evidence together to determine structure.

Check connectivity, functional-group evidence, formula/mass constraint, shifts and integration, splitting neighbours, and agreement across every technique.

3.2.5—IUPAC nomenclature

IUPAC Nomenclature

Naming Organic Compounds

Assessment in practice

Organic Analysis Summary

Question 1