Paracetamol is a medicine commonly used to relieve mild pain - AQA - A-Level Chemistry - Question 8 - 2019 - Paper 2
Question 8
Paracetamol is a medicine commonly used to relieve mild pain. Traditionally, paracetamol has been made industrially in a three-step synthesis from phenol.
Step 1
S... show full transcript
Worked Solution & Example Answer:Paracetamol is a medicine commonly used to relieve mild pain - AQA - A-Level Chemistry - Question 8 - 2019 - Paper 2
Step 1
Name the mechanism of the reaction in Step 1.
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Answer
The mechanism of the reaction in Step 1 is electrophilic substitution.
Step 2
Complete the equation for the reaction in Step 2.
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Answer
The complete equation for the reaction in Step 2 can be represented as:
Complete the mechanism for the reaction of 4-aminophenol with ethanoyl chloride.
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The mechanism involves the nucleophilic attack of the ammonium component of 4-aminophenol on the carbon atom of the carbonyl group in ethanoyl chloride, leading to the formation of paracetamol.
Step 4
Give one reason why ethanoyl chloride is not used in the industrial synthesis.
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One reason why ethanoyl chloride is not used in the industrial synthesis is because it is corrosive and poses a risk to health and safety during its handling.
Step 5
Draw the structure of one of these other aromatic products.
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One possible structure of an aromatic product is 4-nitrochlorobenzene:
Cl
|
C6H4
|
NO2
Alternatively, another product might be 2-nitrophenol.
Step 6
Complete the equation for this second step.
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The complete equation for the second step is:
hydroquinone+NH4​OEt→paracetamol+H2​O
Step 7
Calculate the mass, in kg, of hydroquinone needed to produce 250 kg of paracetamol.
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To find the mass of hydroquinone needed:
Calculate moles of paracetamol:
Moles of paracetamol=151.0g/mol250000g​=1655.6 mol
Use stoichiometry to find moles of hydroquinone, which is equal to moles of paracetamol:
Moles of hydroquinone=1655.6 mol
Calculate mass of hydroquinone:
Mass of hydroquinone=1655.6 mol×110.0 g/mol=18211.9 g=18.2 kg
