Practical: making and testing the smell of some esters in the lab
2 marks · HardState the role of sulfuric acid in the laboratory preparation of an ester. Explain why only a few drops are added.
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Also accept: acts as a catalyst and dehydrating agent; few drops added to avoid excess reactant interfering with yield or causing side reactions
Common mistakes: saying sulfuric acid is a reactant; adding large amounts improves yield
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Marking points
B1 · 1 mark · Correctly states that sulfuric acid is used as a catalyst or dehydrating agent.
B2 · 1 mark · Explains that only a few drops are added because a large amount is not needed or could interfere with the reaction.
Worked solution
Sulfuric acid is added to act as a catalyst and a dehydrating agent in the esterification reaction.
Only a few drops are used because this is enough to catalyse the reaction, and adding more is unnecessary and could interfere with the product or produce unwanted side reactions.