Example 1 · level 1
What is the IUPAC name of HC≡CH?
- ethane
- ethene
- propyne
- ethyne
Show solution
- Structure: HC≡CH.
- A C≡C triple bond gives “-yne”; give it the lowest possible locant.
- IUPAC name: ethyne.
Answer: ethyne
CLASS 11–12 CHEMISTRY · ORGANIC CHEMISTRY: BASIC PRINCIPLES
IUPAC names of simple organic compounds
Pick the longest chain containing the functional group, number it to give the functional group (then substituents) the lowest locants, and add prefixes and the suffix.
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Worked examples
Example 2 · level 2
What is the IUPAC name of CH₃CH₂COOH?
- propanoic acid
- propanal
- ethanoic acid
- butanoic acid
Show solution
- Structure: CH₃CH₂COOH.
- A –COOH group gives “-oic acid”; its carbon counts as C-1.
- IUPAC name: propanoic acid.
Answer: propanoic acid
Example 3 · level 3
What is the IUPAC name of CH₃CONH₂?
- ethanoic acid
- methanamide
- ethanamide
- ethanamine
Show solution
- Structure: CH₃CONH₂.
- A –CONH₂ group gives “-amide”; its carbon counts in the chain.
- IUPAC name: ethanamide.
Answer: ethanamide