This question is about the reaction scheme shown - AQA - A-Level Chemistry - Question 10 - 2022 - Paper 2
Question 10
This question is about the reaction scheme shown.
Step 1
Step 2
Step 3
Step 4
Step 5
Amine B is formed in step 5.
Worked Solution & Example Answer:This question is about the reaction scheme shown - AQA - A-Level Chemistry - Question 10 - 2022 - Paper 2
Step 1
step 1
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Answer
The reagents needed for step 1 are concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).
Step 2
step 2
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Answer
The reagents needed for step 2 are sodium amide (NaNH2) or any similar amine.
Step 3
Give the name of the mechanism for the reaction in step 3.
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The mechanism for the reaction in step 3 is nucleophilic addition-elimination.
Step 4
Name the reagent for step 4.
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The reagent for step 4 is chlorine (Cl2).
Step 5
State a necessary condition for step 4.
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A necessary condition for step 4 is the presence of UV light or elevated temperatures (above 300 °C).
Step 6
Explain why the yield of B in step 5 is less than the yield of A in step 2.
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In step 5, multiple substitutions can occur, leading to further products and reducing the yield of amine B. In contrast, in step 2, the reaction primarily produces only one amine A, resulting in a higher yield.
Step 7
Explain why amine B is a stronger base than amine A.
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Amine B has an alkyl group which donates electron density through inductive effects, enhancing its basicity. In contrast, amine A is influenced by a less electron-donating group, making it a weaker base.
