Explain why ethylamine is a stronger base than ammonia.
[2 marks]
Total for this question: 2
Chemistry
Amines
AQA 3.3.11
A-level Chemistry (7405) · exam-style practice, examiner-report intelligence and the tools that drill it.
Board and spec code confirmed against AQA 7405 · registry checked 2026-07-11How this checking works
The topic on one screen
- Amines are bases: the lone pair on nitrogen accepts a proton (H+).
- The more available that lone pair, the stronger the base. Base strength: aliphatic amines > ammonia > aromatic amines.
- Aliphatic amines: alkyl groups release electron density onto N, so the lone pair is more available → stronger base.
- Aromatic amines (phenylamine): the N lone pair is delocalised into the benzene ring, so it is less available → weaker base.
- Preparation: halogenoalkane + EXCESS ammonia → primary amine; nitrile + LiAlH4 (or H2/Ni) → primary amine; nitrobenzene + Sn/HCl → aromatic amine.
- Amines are nucleophiles too — a primary amine reacts on with more halogenoalkane, so a mixture of amines forms unless ammonia is in excess.
Where students actually lose marks
Base strength has been asked many times but still discriminates well because of the care needed in language: say the lone pair on N is 'more available' (not just 'N is more negative'), and link it to accepting a proton.
June 2024 Paper 2 examiner report (Q09.4)
Few could explain why a halogenoalkane + ammonia gives a mixture: the primary amine formed still has a lone pair, so it reacts further. The single organic product only comes when the amine can't react on.
June 2022 Paper 2 examiner report (Q10.4)
Drawing the amine formed from a nitrile caught many out — too few carbons or missing hydrogens. Count carefully: reducing R-CN adds two H to the carbon and gives R-CH2-NH2.
June 2024 Paper 2 examiner report (Q09.3)
Try it — exam-style
Medium
ORIGINAL · after June 2024 Paper 2 Q09.4
Medium
ORIGINAL
Explain why phenylamine is a weaker base than ammonia.
[2 marks]
Total for this question: 2
Medium
ORIGINAL · after June 2024 Paper 2 Q09.3
State the reagent used to reduce propanenitrile (CH3CH2CN) to an amine, and give the structural formula and name of the product.
[3 marks]
Total for this question: 3
Hard
ORIGINAL · after June 2022 Paper 2 Q10.4
Bromoethane is warmed with ammonia. Explain why a mixture of products forms, and state the condition that maximises the yield of the primary amine.
[3 marks]
Total for this question: 3
Questions are written in the style of past AQA papers (source shown on each) — never copied from them.
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