Chemistry - GOC Question with Solution | TestHub

Option A is correct: Pyridine ($b$) has a localized lone pair, aniline ($c$) has a delocalized lone pair, and pyrrole ($a$) loses its aromaticity upon protonation, making the basic strength order $b>c>a$.

Option B is correct: Electron-donating groups ($+M$) like $-N{H}_2$ ($d$) and $-OMe$ ($c$) increase basicity, whereas electron-withdrawing groups ($-M$) like $-CN$ ($b$) and $-N{O}_2$ ($a$) decrease it ($d>c>b>a$).

Option C is correct: Meta-nitroaniline ($b$) is the strongest base because $-M$ resonance does not operate at the meta-position, while ortho-nitroaniline ($c$) is the weakest due to the ortho effect ($b>a>c$).

Option D is incorrect: The two methyl groups in ($b$) cause Steric Inhibition of Resonance (SIR), rotating the $-N{O}_2$ group out of plane; this eliminates its $-M$ effect and makes ($b$) a stronger base than ($a$) ($b>a$).