text: Try the keywords substitution reactions of naphthol on yahoo. Here is a little of what I found:\nDiazonium ions are present in solutions such as benzenediazonium chloride solution. They contain an -N2+ group. In the case of benzenediazonium chloride, this is attached to a benzene ring.\n\nIn this set of reactions of the diazonium ion, the -N2+ group is replaced by something else. The nitrogen is released as nitrogen gas.\n\nThis is a good example of the use of diazonium salts to substitute things into a benzene ring which are otherwise quite difficult to attach. (That's equally true of the previous reaction, by the way.)\n\nIf you add potassium iodide solution to the benzenediazonium chloride solution in the cold, nitrogen gas is given off, and you get oily droplets of iodobenzene formed.\nThere is a simple reaction between the diazonium ions and the iodide ions from the potassium iodide solution.\n\nI found this information at the sources listed below-try it out.