A-LevelChemistryHalogen derivativesOct/Nov 2018Paper 1 Q381 Mark
Halogenoalkanes can undergo reaction with hydroxide ions. RBr + OH⁻ → ROH + Br⁻ The reaction of some halogenoalkanes proceeds by the SN1 mechanism. Which statements about the SN1 mechanism are correct? 1 A carbocation is formed which is stabilised by the inductive effect of the alkyl groups present. 2 Only tertiary halogenoalkanes are hydrolysed in this way. 3 The intermediate formed includes a carbon atom with five bonds attached to it.
A1, 2 and 3 are correct
B1 and 2 only are correct
C2 and 3 only are correct
D1 only is correct
✓ Correct Answer
The correct answer is D: 1 only is correct
📋 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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