Arrange the following in increasing order of their basic strength
(I) \(C_6H_5NH_2\) (II) \(C_2H_5NH_2\) (III) \(NH_3\)
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → I < III < II
Basic strength depends on how readily the lone pair on nitrogen is available to accept a proton.
(I) C6H5NH2 — the lone pair on N is delocalised into the benzene ring by resonance, so it is least available: weakest base.
(III) NH3 — no group to release or withdraw electrons; it lies in between.
(II) C2H5NH2 — the ethyl group releases electrons (+I effect), increasing the electron density on N and stabilising the cation formed: strongest base of the three.