The correct increasing order of basic strength for the following compounds is :
II < III < I
III < I < II
III < II < I
II < I < III
As we learnt in
Basicity of Aromatic Amines -
The unshared pair of electrons at the nitrogen atom is in resonance with the benzene ring and hence not fully available for donation as in the case of aniline.
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e- donating group increases basicity e- withdrawing group decreases basicity
Option 1)
II < III < I
This option is incorrect
Option 2)
III < I < II
This option is incorrect
Option 3)
III < II < I
This option is incorrect
Option 4)
II < I < III
This option is correct
Option 2 is the answer because the +I EFFECT increase the electron density on nitrogen in I structure
-I effect decreases the electron density in II structure