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A reaction pathway diagram is shown - CIE - A-Level Chemistry - Question 29 - 2012 - Paper 1
Question 29
A reaction pathway diagram is shown. A reaction pathway diagram is shown below:  Which reaction does not have such a pro... show full transcript
Worked Solution & Example Answer:A reaction pathway diagram is shown - CIE - A-Level Chemistry - Question 29 - 2012 - Paper 1
Step 1
Which reaction does not have such a profile?
Answer
To identify which reaction does not follow the energy profile illustrated in the diagram, we must analyze the reactions:
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Option A: The reaction of CH₃CHO with HCN leading to CH₃(CH)(OH)CN involves a transition state that is likely to have a peak in energy, indicating it does follow the required profile.
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Option B: The reaction of C₂H₅Br with NaOH to produce C₂H₅OH and NaBr typically has an increasing and decreasing energy profile, which aligns with the provided diagram as it reflects a transition state in the process.
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Option C: The reaction of (CH₃)₃CBr with NaOH leading to (CH₃)₃COH and NaBr also has a transition peak due to the formation of intermediates, consistent with the diagram's profile.
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Option D: The reaction represented is a straightforward halogenation and would not have a transition state requiring an energy peak; hence it does not fit the reaction pathway profile shown.
Based on this analysis, the answer is B as it represents a reaction that does not have such an energy profile.