CAIE A Level Chemistry 9701 · Carbonyl compounds
A student carries out tests on two carbonyl compounds, P and Q, both with the molecular formula . The results are shown.
| Test | P | Q |
|---|---|---|
| Tollens' reagent | silver mirror formed | no change |
| Fehling's solution | red precipitate formed | no change |
| alkaline aqueous iodine | no precipitate | yellow precipitate |
Explain what these results show about the structures of P and Q.
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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