‹ Chemistry simulationsChemistry · A Level 9701 · 33 Carboxylic acids and derivatives (A Level)Five simulations covering Topic 33: how chlorine, alkyl and phenyl groups change the strength of a carboxylic acid; the two acids that can be oxidised, methanoic and ethanedioic, tested with Tollens' reagent, Fehling's solution and acidified potassium manganate(VII); ethanoic acid turned into ethanoyl chloride with PCl5, PCl3 or SOCl2 in 3D; a hydrolysis race between ethanoyl chloride, chloroethane and chlorobenzene; and the addition-elimination mechanism of ethanoyl chloride with water, ethanol, ammonia and methylamine, stepped through in 3D with the curly arrows.
A carboxylic acid is only as strong as its anion is stable. Anything attached to the carboxyl carbon that pulls electron density away helps to spread the negative charge on the carboxylate ion, so the acid gives up its proton more readily. Anything that pushes electron density in does the opposite. Pick a group and watch the pKa and the charge change.
Most carboxylic acids are already fully oxidised and do not react with oxidising agents. Two are different: methanoic acid has a hydrogen on the carboxyl carbon, like an aldehyde, and ethanedioic acid has two carboxyl groups joined together. Choose an acid and a reagent, add the acid and warm the tube.
To make ethanoyl chloride, the OH of the carboxyl group is swapped for a chlorine atom. Three reagents will do it: phosphorus(V) chloride, phosphorus(III) chloride and sulfur dichloride oxide (thionyl chloride). Pick one and step through to see the products and the conditions.
Three compounds all contain a carbon-chlorine bond, but they behave very differently with cold water. Add a few drops of each to water, then test the solution with acidified silver nitrate to see whether any chloride ions were released.
Acyl chlorides react with nucleophiles in two stages. The nucleophile adds to the carbonyl carbon, and then the chlorine is eliminated as the carbon-oxygen double bond is restored. Pick a nucleophile and step through, watching the curly arrows.
Five interactive simulations for Cambridge A Level Chemistry 9701 topic 33 Carboxylic acids and derivatives: the pKa and charge distribution of substituted carboxylate ions, a bench for the oxidation of methanoic and ethanedioic acids with Tollens' reagent, Fehling's solution and acidified potassium manganate(VII), a 3D view of ethanoic acid becoming ethanoyl chloride with phosphorus pentachloride, phosphorus trichloride or thionyl chloride, a hydrolysis race of ethanoyl chloride against chloroethane and chlorobenzene with silver nitrate and bond polarity, and the nucleophilic addition-elimination mechanism of ethanoyl chloride with water, ethanol, ammonia and methylamine in 3D with curly arrows.
Five simulations covering Topic 33: how chlorine, alkyl and phenyl groups change the strength of a carboxylic acid; the two acids that can be oxidised, methanoic and ethanedioic, tested with Tollens' reagent, Fehling's solution and acidified potassium manganate(VII); ethanoic acid turned into ethanoyl chloride with PCl5, PCl3 or SOCl2 in 3D; a hydrolysis race between ethanoyl chloride, chloroethane and chlorobenzene; and the addition-elimination mechanism of ethanoyl chloride with water, ethanol, ammonia and methylamine, stepped through in 3D with the curly arrows.
Carboxylic acids and derivatives (A Level) is a free, browser-based simulation for Cambridge International AS & A Level Chemistry 9701 (topic 33 Carboxylic acids and derivatives). 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: A Level Chemistry 9701 topic 33.
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