JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Compounds Containing Nitrogen

The aryldiazonium cation carries a positive charge on the terminal nitrogen that is delocalised into the ring, so groups which push electron density towards this centre stabilise it while electron-withdrawing groups destabilise it. The para substituents are $-\mathrm{OC}{\mathrm{H}}_3$ in A (strong $+M$ donor), none in C (reference), $-\mathrm{CN}$ in D (strong $-M$ acceptor) and $-\mathrm{N}{\mathrm{O}}_2$ in B (an even stronger $-M$ acceptor). Stability therefore runs from the donor-substituted ring, through the unsubstituted ring, to the two acceptor-substituted rings, the stronger acceptor being least stable. The decreasing order of stability is $\mathrm{A}>\mathrm{C}>\mathrm{D}>\mathrm{B}$.