Consider the following diazonium ions: (I) p-Methoxybenzenediazonium (II) Benzenediazonium (III) m-Methoxybenzenediazonium (IV) p-Nitrobenzenediazonium The correct decreasing order of their stability is:

Step-by-step solution

The stability of a diazonium cation is directly proportional to the electron-donating ability of the substituent on the benzene ring. In (I), the -OCH3 group is at the para position. It exhibits a strong +M (mesomeric) effect which dominates over its -I effect, highly stabilizing the cation. In (II), there is no substituent (reference point). In (III), the -OCH3 group is at the meta position. Resonance (+M) effects do not operate from the meta position. Therefore, only its -I (inductive) effect operates, which with