Case study·Hard exam skill (4/5)·No calculator
Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
Identify the aldehyde-or-ketone contents of four bottles labelled P, Q, R and S. The possible compounds are methanal, ethanal, propanone and benzaldehyde, not in order. The observations ar; Q gives Tollens' test, no iodoform test and does not reduce Fehling's solution; R gives 2,4-DNP but no Tollens' test and gives iodoform test; S gives Tollens' test, no iodoform test and reduces Fehling's solution.
Total: 4 marks
(a) Identify P. (1 mark)
(b) Identify Q. (1 mark)
(c) Identify R. (1 mark)
(d) Identify S. (1 mark)
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