CAIE A Level Chemistry 9701 · Carbonyl compounds
Propanone reacts with hydrogen cyanide to form 2-hydroxy-2-methylpropanenitrile.
The reaction is very slow if hydrogen cyanide is used alone, but it proceeds readily when potassium cyanide is added and the mixture is heated.
Explain why potassium cyanide must be present and how this reaction occurs.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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