Polystyrene can be made from benzene in the series of steps shown - AQA - A-Level Chemistry - Question 6 - 2020 - Paper 2
Question 6
Polystyrene can be made from benzene in the series of steps shown.
**0.6.1** State the type of reaction in step 1. Identify the reagent(s) and conditions needed for... show full transcript
Worked Solution & Example Answer:Polystyrene can be made from benzene in the series of steps shown - AQA - A-Level Chemistry - Question 6 - 2020 - Paper 2
Step 1
State the type of reaction in step 1. Identify the reagent(s) and conditions needed for step 1.
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Answer
Type of reaction: Acylation Reagent(s): CH₃COCl or Ethanoic chloride Conditions: AlCl₃ (Aluminum chloride) as a catalyst
Step 2
State the name of the mechanism for the reaction in step 2. Identify the inorganic reagent needed for step 2. Name the organic product of step 2.
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Answer
Name of mechanism: Nucleophilic addition Inorganic reagent: NaBH₄ (Sodium borohydride) Name of organic product: 1-Phenylethanol
Step 3
Outline the mechanism for step 3.
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Answer
In step 3, the organic product from step 2 reacts with concentrated sulfuric acid. The mechanism involves:
Protonation of the alcohol group, making it a better leaving group.
Elimination of water to form a carbocation.
Attack of the carbocation by the sulfuric acid, leading to the formation of an alkyl hydrogen sulfate.
Step 4
Draw the repeating unit of polystyrene.
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Answer
The repeating unit of polystyrene consists of a phenyl group attached to a carbon chain. It can be depicted as:
