Case study·Standard multi-step (3/5)·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
Three bases are labelled P, Q and R. P is aniline, Q is cyclohexylamine, and R is p-nitroaniline. Equal amounts are shaken separately with dilute hydrochloric acid and then compared for tendency to form ammonium salts.
Total: 4 marks
(a) Which base is strongest? (1 mark)
(b) Which base is weakest? (1 mark)
(c) Explain the role of resonance in P. (1 mark)
(d) Explain the role of the nitro group in R. (1 mark)
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