The correct stability order of the following diazonium salts is [figure]
- C > D > B > A
- A > C > D > B
- A > B > C > D
- C > A > D > B
Answer
(2) A > C > D > B
Solution
Arenediazonium ions are stabilised by delocalisation of the positive charge into the ring. An electron-donating group at the para position increases this delocalisation, an electron-withdrawing group decreases it.
A: –OCH3 (+R) donates electrons to the ring most stable.
C: no substituent.
D: –CN (–R, –I) withdraws electrons less stable than C.
B: –NO2 (strongest –R, –I) least stable.
A > C > D > B
Answer: (2)