‹ Chemistry simulationsChemistry · AS Level 9701 · 19 Nitrogen compoundsFive simulations covering Topic 19: ammonia attacking a halogenoalkane to make a primary amine, with the inversion at carbon and the reason for using excess ammonia; why amines are bases and how strong they are; the cyanide ion adding a carbon to the chain; HCN adding across a carbonyl group to make a hydroxynitrile; and what nitriles turn into when they are hydrolysed or reduced.
Ammonia has a lone pair, and a halogenoalkane has a carbon that is short of electrons because the halogen pulls them away. Put the two together, warm them in ethanol in a sealed tube, and the lone pair attacks the carbon while the halogen leaves as an ion. Step through it and watch the carbon turn inside out.
The same lone pair that attacks a halogenoalkane will also pick up a proton, which makes every amine a base. An alkyl group pushes electron density onto the nitrogen and makes the lone pair more available, so ethylamine is a stronger base than ammonia. Compare them, then add an acid.
The cyanide ion is a nucleophile too, and it is the one organic chemists reach for when they need the carbon chain to grow. Heat a halogenoalkane with potassium cyanide in ethanol and the CN group takes the place of the halogen. Count the carbons before and after.
A carbonyl carbon is electron-poor because the oxygen pulls the shared electrons towards itself. The cyanide ion attacks it from above or below the flat molecule, the double bond opens, and a proton finishes the job. The product is a hydroxynitrile, with one more carbon than the aldehyde or ketone you started with.
A nitrile is rarely the final target. Its triple bond can be hydrolysed to a carboxylic acid, or reduced to a primary amine, so making the nitrile first is a way of reaching those compounds with an extra carbon in the chain. Pick a nitrile and a reaction and see the product beside it.
Five interactive simulations for Cambridge AS Level Chemistry 9701 topic 19 Nitrogen compounds: nucleophilic substitution of a halogenoalkane by ammonia stepped through in 3D with the lone pair, the curly arrows and the umbrella inversion at carbon, a base-strength comparison of ammonia, methylamine and ethylamine with the pH of a tenth-molar solution worked out and the salt formed with hydrochloric acid, the cyanide ion lengthening the carbon chain by one, nucleophilic addition of HCN to ethanal and propanone to give hydroxynitriles, and the hydrolysis and reduction of nitriles to carboxylic acids and primary amines.
Five simulations covering Topic 19: ammonia attacking a halogenoalkane to make a primary amine, with the inversion at carbon and the reason for using excess ammonia; why amines are bases and how strong they are; the cyanide ion adding a carbon to the chain; HCN adding across a carbonyl group to make a hydroxynitrile; and what nitriles turn into when they are hydrolysed or reduced.
Nitrogen compounds is a free, browser-based simulation for Cambridge International AS & A Level Chemistry 9701 (topic 19 Nitrogen compounds). The course is assessed in Paper 1 (Multiple Choice (AS)), Paper 2 (AS Structured), Paper 3 (Advanced Practical), Paper 4 (A Level Structured), Paper 5 (Planning, Analysis, Evaluation). Syllabus for examination in 2025-2027. There are 5 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.
Full syllabus map: AS Level Chemistry 9701 topic 19.
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