A-LevelChemistryCarbonyl compoundsMay/June 2023Paper 1 Q351 Mark
The mechanism for the reaction between ethanal and hydrogen cyanide starts with the step shown. [Figure of reaction mechanism, step 1] What is the correct structure of the intermediate ion formed, and what is the next step in this mechanism?
ADiagram showing the intermediate ion H₂C(CN)O⁻ and its protonation by H⁺
BDiagram showing the intermediate ion H₂C(CN)O⁻ with an incorrect subsequent reaction arrow
CDiagram showing the intermediate ion H₂C(CN)O⁻ with an incorrect subsequent reaction arrow
DDiagram showing the intermediate ion H₂C(CN)O⁻ and its protonation by H⁺
✓ Correct Answer
The correct answer is D. This question tests the candidate's understanding of carbonyl compounds within the Chemistrysyllabus. The examiner's mark scheme requires...
📋 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...
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