AQA A-Level Chemistry Paper 3, 2021: Question 31
1 mark · Medium difficulty · Multiple Choice
This question checks your understanding of how different organic compounds react with dilute aqueous sodium hydroxide. It focuses on identifying which compound among the options is capable of undergoing hydrolysis under these conditions. Only certain functional groups will react, particularly those involving acyl groups like in acid anhydrides.
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Question text
31 Which compound reacts with warm dilute aqueous sodium hydroxide?
[1 mark]
A C6H6
B CH3CH=CH2
C CH3CH2CH2NH2
D (CH3CO)2O
Mark scheme
Show the mark scheme
31 D 1 (CH3CO)2O
How to answer it
Multiple Choice Explained: Which compound reacts with warm dilute aqueous sodium hydroxide?
Correct Answer: D – (CH3CO)2O
Why? This is ethanoic anhydride, an acyl compound that undergoes hydrolysis with warm, dilute sodium hydroxide to form sodium ethanoate. Acyl compounds readily react with nucleophiles like OH⁻.
Why A is incorrect:
C6H6 (benzene) is very stable due to delocalised π-electrons. It is unreactive towards NaOH under normal conditions and does not undergo nucleophilic substitution or hydrolysis.
Why B is incorrect:
CH3CH=CH2 (propene) is an alkene and typically undergoes electrophilic addition reactions. It doesn’t react with dilute NaOH in the way the question describes.
Why C is incorrect:
CH3CH2CH2NH2 (propylamine) is a weak base, and while it might react with strong acids, it doesn’t undergo any significant reaction with NaOH in aqueous conditions.
Topics
Organic Chemistry · 3.3.9 Carboxylic Acids and Derivatives
Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.