question_answer 71)

  Under what reaction conditions (acidic, basic), the coupling reaction of aryldiazonium chloride with aniline is carried out?                                                                  

Answer:

                  Under strongly basic conditions, benzenediazonium chloride is converted into diazohydroxide/diazoate both of which are not electrophilic and hence do not couple with aniline.                          On the other hand, in highly acidic conditions, aniline gets converted into anilinium ion. As a result, aniline is no longer hucleophilic acid hence will not couple with diazonium chloride. Therefore, the reaction is' carried out under mild conditions, i.e., pH 4-5.