This question is about amines - AQA - A-Level Chemistry - Question 10 - 2018 - Paper 2
Question 10
This question is about amines.
The infrared spectra A, B and C are those of a primary amine, a tertiary amine and a nitrile, but not necessarily in that order.
A
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Worked Solution & Example Answer:This question is about amines - AQA - A-Level Chemistry - Question 10 - 2018 - Paper 2
Step 1
Give the letter of each compound in the correct box.
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Answer
A: primary amine
B: tertiary amine
C: nitrile
Step 2
Draw the skeletal formulas of these three secondary amines.
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Answer
CH3CH2CH(NH2)CH3
(CH3)2CHNH(CH2)2CH3
CH3(CH2)2N(CH2)2CH3
Step 3
Justify the statement that it is better to prepare primary amines from nitrites rather than from halogenoalkanes.
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When preparing primary amines from halogenoalkanes, there is a risk of further reactions leading to multiple products. In contrast, using nitrites allows for a more direct conversion with fewer by-products, resulting in higher atom economy.
Step 4
Draw the structure of a primary amine with four carbon atoms that cannot be formed from a nitrile.
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The structure is as follows:
CH3CH2CH2CH2NH2
Step 5
Give an equation for the reaction that occurs.
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C3H7NH2 + H2O → C3H7NH3^+ + OH^-
Step 6
Describe what is observed when Universal Indicator is added to this solution.
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The solution turns blue, indicating it is basic.
Step 7
Give an equation for the reduction of nitrobenzene to form phenylamine.
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C6H5NO2 + 6[H] → C6H5NH2 + 2H2O
Step 8
Explain why an aqueous solution is obtained in this reduction even though phenylamine is insoluble in water.
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During the reduction process, phenylamine forms a salt with hydrochloric acid in solution, leading to the formation of an ionic compound that is more soluble in water.
