From the above reactions, it is clear that the diazonium salts are very
good intermediates for the introduction of –F, –Cl, –Br, –I, –CN, –OH,
–NO2 groups into the aromatic ring Aryl fluorides and iodides cannot be prepared by direct halogenation The cyano group cannot be introduced by nucleophilic substitution of
chlorine in chlorobenzene but cyanobenzene can be easily obtained
from diazonium salt Thus, the replacement of diazo group by other groups is helpful in
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