Question

For the following amines basic strength. Reason ​

Answer 1

1. Amines are basic because of the lone pair of electrons on N, which it can use to donate to a lewis acid and hence acts as a lewis base.
2. Thus, electron releasing groups ( ERG) increase electron density and henCe increases the basicity of amines. Electron withdrawing group do the opposite (EWG).
3. aniline is weaker than aliphatic amines as the lone pair on N is involved in resonance

Based on these information, we can use to solve the problem

1. The most basic here is Benzylamine (iii) as the lone pair of nitrogen is not involved in resonance and hence can be easily donated to an acid.
2. The next basic is N-methylaniline (i) due to the strong +I alkyl group that increases electron density on N
3. The next most basic is methoxyaniline (ii) because -OCH₃ is an ERG and hence increases electron density at ortho/para positions
4. Least basic is aniline as it has no ERG and the lone pair will be used in resonance with the ring. (iv)

(iii) > (i) > (ii) > (iv)