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Analyse how a student could design a chemical synthesis process to be undertaken in the school laboratory - HSC - SSCE Chemistry - Question 33 - 2022 - Paper 1
Question 33
Analyse how a student could design a chemical synthesis process to be undertaken in the school laboratory. In your response, use a specific process relating to the s... show full transcript
Worked Solution & Example Answer:Analyse how a student could design a chemical synthesis process to be undertaken in the school laboratory - HSC - SSCE Chemistry - Question 33 - 2022 - Paper 1
Step 1
selection of reagent(s)
Answer
For the synthesis of methyl ethanoate, the primary reagents chosen are methanol and ethanoic acid. These substances are easily accessible in a school laboratory. Methanol acts as the alcohol, while ethanoic acid serves as the carboxylic acid. The reaction is catalyzed by concentrated sulfuric acid, which not only enhances the reaction rate but also helps in driving the equilibrium towards the production of the ester.
Step 2
reaction conditions
Answer
The reaction should be performed under reflux conditions to maintain a consistent temperature and to prevent the loss of volatile reactants. It is essential to carry out the reaction in a fume cupboard due to the use of methanol and concentrated sulfuric acid. The acid should be added dropwise to ensure safety and to avoid vigorous reactions. Reflux allows for sufficient heating (approximately 30 minutes) while preventing pressure buildup.
Step 3
any potential hazards and any safety precautions to minimise the risk
Answer
The handling of methanol and concentrated sulfuric acid poses several hazards, including flammability and corrosiveness. Therefore, it is crucial to wear appropriate personal protective equipment, such as safety goggles and gloves. Additionally, reactions involving alcohols should be conducted away from open flames; a heating mantle is preferred over a Bunsen burner to mitigate fire risk.
Step 4
yield and purity of the product(s)
Answer
To maximize the yield of methyl ethanoate, the reaction should proceed at a higher temperature with extended reflux. After completing the reaction, purification steps like distillation can be employed to separate the ester from unreacted starting materials and side products. Monitoring the purity can be conducted using techniques such as infrared spectroscopy or thin-layer chromatography to ensure that methyl ethanoate is the predominant product.