This question is about esters - AQA - A-Level Chemistry - Question 7 - 2022 - Paper 2
Question 7
This question is about esters.
Figure 4 shows an incomplete mechanism for the reaction of an ester with aqueous sodium hydroxide.
Figure 4
1. Add three curly arro... show full transcript
Worked Solution & Example Answer:This question is about esters - AQA - A-Level Chemistry - Question 7 - 2022 - Paper 2
Step 1
Add three curly arrows to complete the mechanism in Figure 4.
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Answer
To complete the mechanism in Figure 4, three curly arrows are needed:
First Arrow: Draw an arrow from the carbon atom of the C=O bond to the oxygen atom, indicating nucleophilic attack by hydroxide.
Second Arrow: Place an arrow from the C-O bond to the adjacent carbon atom, showing the bond breaking.
Third Arrow: Draw an arrow from the O-H bond of the hydroxide ion to the carbonyl carbon to show the formation of the alkoxide.
Step 2
Name the type of reaction shown in Figure 4.
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Answer
The type of reaction shown in Figure 4 is an alkaline hydrolysis, also known as saponification.
Step 3
Deduce the role of the CH3O- ion in step 3 shown in Figure 4.
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Answer
In step 3, the CH3O- ion acts as a base. It accepts a proton from the hydroxyl group formed during the reaction, thereby stabilizing the intermediate and facilitating the completion of the hydrolysis reaction.
Step 4
Give a use for a product of this reaction.
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Answer
A product of this reaction is soap, which can be used for cleaning and emulsifying substances.
