A-LevelChemistryReaction kineticsOct/Nov 2018Paper 5 Q114 Marks
The Finkelstein reaction is a nucleophilic substitution reaction in which a halogen atom in a halogenoalkane is replaced by another halogen atom. The reaction is carried out using dry propanone as a solvent. One example of the Finkelstein reaction is given. CH3CH2CH2Br + NaI ⇌ CH3CH2CH2I + NaBr (pr) = substance is dissolved in propanone The student plans to record the time it takes for the solid formed to obscure a cross on a piece of paper below the conical flask, as shown. [Figure X.X] To carry out this experiment, the following materials are available. • CH3CH2CH2Br(l) • NaI(s) • dry propanone, CH3COCH3(l) • usual laboratory apparatus
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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