A-LevelChemistryCarbonyl compounds9701/12 · May/June 2023 · 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?

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

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

D: Diagram showing the intermediate ion H₂C(CN)O⁻ and its protonation by H⁺

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Topic: Carbonyl compounds, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, May/June 2023 Paper 1 Variant 2, question 35.

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