AS · Practice questions · Naming organic compounds

Name it, draw it.

Six original Cambridge-style questions on naming organic compounds.

Original questions All questions on this page are original work, written in the Cambridge AS & A Level style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Longest chain, lowest numbers, alphabetical prefixes.

Stem from the longest chain including the functional group.
Suffix from the main group; halogens and alkyl groups are prefixes.
Lowest locants; di/tri for repeats.
Esters: alkyl + -oate.

Recall

[4 marks]

Name: (a) CH₃CH(OH)CH₂CH₃, (b) CH₃COCH₃, (c) HCOOCH₃, (d) CH₃CH₂CH₂COOH.

(a) butan-2-ol. ✓
(b) propanone. ✓
(c) methyl methanoate. ✓
(d) butanoic acid. ✓

Recall

[3 marks]

Draw structural formulae for (a) 2-methylpropan-1-ol, (b) pent-2-ene, (c) 1,2-dibromoethane.

(a) (CH₃)₂CHCH₂OH. ✓
(b) CH₃CH=CHCH₂CH₃. ✓
(c) CH₂BrCH₂Br. ✓

Analysis

[2 marks]

A student names a compound 4-methylpentane. Explain the error and give the correct name.

The chain should be numbered from the other end to give the methyl group the lowest locant. ✓
Correct name: 2-methylpentane. ✓

Analysis

[2 marks]

A student names CH₃CH₂CH(CH₂CH₃)CH₃ as 2-ethylbutane. Explain why this is wrong and give the correct name.

The longest chain runs through the ethyl group: it has five carbons, not four. ✓
Correct name: 3-methylpentane. ✓

Recall

[2 marks]

Name the ester formed from propanoic acid and methanol, and give its structural formula.

Methyl propanoate. ✓
CH₃CH₂COOCH₃. ✓

Recall

[2 marks]

Name CH₃CHClCH₂Br and CH₃CH₂CH₂NH₂.

1-bromo-2-chloropropane (prefixes in alphabetical order). ✓
Propylamine (propan-1-amine). ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.