CAIE A Level Chemistry 9701 · Carboxylic acids and derivatives

Carboxylic acids and derivatives: explain question

Explain6 marksChallenge

A student prepares propanoic acid from propanenitrile, $\ce{CH3CH2CN}$ . Two methods are tried.

Method 1: propanenitrile is refluxed with dilute sulfuric acid, then the mixture is neutralised and the product is isolated.

Method 2: propanenitrile is refluxed with dilute aqueous sodium hydroxide, then the mixture is acidified and the product is isolated.

Both methods give the same organic product.

Explain why both methods give the same organic product, and state the role of the sulfuric acid in Method 1 and of the sodium hydroxide in Method 2.

How this question is marked

6 marks, so the mark scheme is looking for about 6 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.

Carboxylic acids and derivatives: explain question

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