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:
... show full transcript
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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The reagents needed for step 1 are concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4). These acids are used to nitrate the methyl group on the benzene ring.
Step 2
step 2
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The reagents required for step 2 are tin (Sn) and hydrochloric acid (HCl). This reduction process converts the nitro group (-NO2) to an amino group (-NH2) to form Amine A.
Step 3
1.2 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
1.3 Name the reagent for step 4.
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The reagent for step 4 is chlorine (Cl2). This adds chlorine to the benzene ring.
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 high temperature (above 300°C) to facilitate the reaction.
Step 6
1.4 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, further substitution can occur, leading to multiple products instead of a single product, therefore decreasing the yield of amine B compared to amine A, which was formed directly.
Step 7
1.5 Explain why amine B is a stronger base than amine A.
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Amine B possesses an acyl group (–C(=O)R) that exerts an electron-withdrawing effect, making the lone pair on nitrogen more available for protonation, thus increasing its basicity compared to amine A.
