CAIE A-Level Chemistry 34.2.3 Basicity of Ammonia, Ethylamine and Phenylamine
Practise ranking aqueous ammonia, alkylamines and phenylamine by nitrogen lone-pair availability.
- Syllabus
- 2028–2030
- Course
- Chemistry 9701
- Level
- A2
Exam points
- rank phenylamine below ammonia below ethylamine or another simple alkylamine in aqueous solution
- delocalise phenylamine’s nitrogen lone pair into the benzene π system, making proton acceptance less favourable
- use the alkyl group’s positive inductive effect to increase nitrogen electron density and amine basicity
34.2.3—Basicities of aq. ammonia, ethylamine question 1
[Maximum number: 3]
Describe the relative basicities of ammonia, ethylamine and phenylamine, starting with the least basic.
Explain your answer in terms of their structures. < <
least basic
most basic
phenylamine < ammonia < ethylamine [1]
- Ip on nitrogen of phenylamine delocalised into ring
- alkyl group of ethylamine electron donating / has positive inductive effect [1]
- correct statement about availability of lone pair to accept proton once [1]
All question bank results loaded