Name amines, nitriles and esters within AS limits
Name primary amines, nitriles and esters while respecting the syllabus chain and carbon-count restrictions.
Section 13 · An introduction to AS Level organic chemistry
AS Level; Cambridge International Chemistry 9701, 2025–2027 syllabus. Use the published functional-group scope and nomenclature limits; draw formula and mechanism evidence with correct connectivity, electron movement and stereochemistry. Written practice is self-checked
Before you begin
- Use covalent structures, valency, molecular formulas, lone pairs, and single, double and triple bonds.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which atom group defines a nitrile?
What you will learn
- Recognise primary amine and nitrile names
- Name an ester from its alcohol-derived and acid-derived parts
- Apply the six-plus-six and straight-chain ester limits
Amines and nitriles have distinct nitrogen groups
The AS table includes primary amines, with –NH₂, and nitriles, with –C≡N. A straight-chain three-carbon primary amine can be called propylamine in the syllabus table; systematic suffix form propan-1-amine makes the attachment position explicit.
For a nitrile, the carbon of –C≡N counts as part of the parent chain. For example, CH₃CH₂C≡N is propanenitrile, with three carbons total.
Ester names identify two sides
An ester has the linkage –COO–. Name the alkyl group attached to the oxygen first, then the acid-derived alkanoate part, for example CH₃COOCH₂CH₃ is ethyl ethanoate.
For AS nomenclature, ester chains are straight chains only, with up to six carbons on each side (six plus six). Do not apply the unconstrained branched naming rules for esters or nitriles beyond the stated scope.
Pause and explain
In an ester name, what is named first?
Worked example
Name CH₃COOCH₂CH₂CH₃ and CH₃CH₂C≡N, and count the ester carbons by side.
Show the worked solution
- The ester has propyl on the oxygen side.
- Its acid-derived side has two carbons, including the carbonyl carbon.
- The nitrile has three total carbons, including C≡N.
Answer The ester is propyl ethanoate (three plus two carbons); the nitrile is propanenitrile.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Name CH₃CH₂COOCH₃.
Give me a hint
Identify the oxygen-side alkyl group and the acid-side carbon count.
Compare my reasoning
- The oxygen is attached to a methyl group.
- The acid-derived side contains three carbons including C=O.
- Write alkyl first, then alkanoate.
Methyl propanoate.
Look for these in your work
- Alkyl side identified
- Acid chain counted
- Name order correct
Name CH₃CH₂CH₂NH₂ and CH₃CH₂C≡N.
Give me a hint
Identify the primary amine and count the nitrile carbon as part of its parent.
Compare my reasoning
- CH₃CH₂CH₂NH₂ is a straight-chain three-carbon primary amine.
- Its systematic name is propan-1-amine; the syllabus table also uses propylamine.
- CH₃CH₂C≡N has three carbons including C≡N, so it is propanenitrile.
Propan-1-amine (propylamine) and propanenitrile.
Look for these in your work
- Amine chain and group
- Accepted amine name
- Nitrile carbon counted
An ester is described as having a straight three-carbon alkyl side and a straight six-carbon acid-derived side. Is it within the AS naming scope?
Give me a hint
Check each side separately against the six-plus-six limit.
Compare my reasoning
- The oxygen-side chain has three carbons.
- The acid-derived side has six carbons including its carbonyl carbon.
- Both sides are straight and no side exceeds six, so it is within the stated naming scope.
Yes. It is a straight-chain ester with three carbons on one side and six on the other, within the six-plus-six limit.
Look for these in your work
- Each side counted
- Carbonyl count understood
- Scope decision justified
Common mistakes
- Naming an ester in reverse order
- Leaving the nitrile carbon out of the chain count
- Exceeding or ignoring the syllabus ester-chain limit
What can you explain now?
Which atom group defines a nitrile?
Compare with the explanation
–C≡N
A nitrile contains a carbon–nitrogen triple bond.
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Make it stick
Which carbon is included in the nitrile parent-chain count?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.