Consider the following four compounds I, II, III, and IV. Choose...

The correct basic strength order is

(A) ${K}_{b}: IV > II > ∣ > III;$

• $IV$ is strongest base due to SIR effect.
• $III$ is weakest base due to$- M$ group of three nitro groups present at Ortho and Para positions.
• $Il$ is stronger than $I$ since $III$ is tertiary and $I$ primary aromatic amine.

(B) $IV$ is found to be $40, 000$ times more basic than $III$. While $I and$II$differ very little in basic strength.</p><p>(C,D) Due to SIR effect in$IV$both$- {NO}_{2}$and$- N{\left({CH}_{3}\right)}_{2} will be out of plane hence resonance effect is more in $III$ than in $IV$.
in III than in $\mathrm{V}$.