Replacement by iodide ion: Iodine is not easily introduced into
the benzene ring directly, but, when the diazonium salt solution
is treated with potassium iodide, iodobenzene is formed 3 Replacement by fluoride ion: When arenediazonium chloride is
treated with fluoroboric acid, arene diazonium fluoroborate is
precipitated  which on heating decomposes to yield aryl fluoride 4