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 nitrite, 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: Nitrite
Step 2
Draw the skeletal formulas of these three secondary amines.
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Step 3
Justify the statement that it is better to prepare primary amines from nitrites rather than from halogenoalkanes.
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Primary amines synthesized from nitrites usually yield a single product and provide a better atom economy compared to the possible formation of multiple by-products when using halogenoalkanes.
Step 4
Draw the structure of a primary amine with four carbon atoms that cannot be formed from a nitrite.
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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 that it is basic due to the formation of propylammonium ions.
Step 7
Give an equation for the reduction of nitrobenzene to form phenylamine. Use [H] to represent the reducing agent.
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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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Phenylamine can form salts when reacted with hydrochloric acid, which are soluble in water, leading to the formation of an aqueous solution.
