Which of the following conditions is most satisfactory for diazo coupling with amines ?

Options

A. Strong acidic
B. Mildly basic
C. Strongly basic
D. Mildly acidic

Answer

D

Explanation

Strongly basic conditions are unsatisfactory for diazo coupling because neither the diazoic acid nor its anion couple Strongly acidic conditions are also unsatisfactory for diazo coupling because strong acid converts `ArNH_(2)` to `ArNH_(3)+` whose ring is deactivated to coupling Hence amines couple fastest in mildly acidic solutions In mildly basic conditions amines become insoluble Also note that to avoid coupling of `Ar^(+)N_(2)` with unreacted `ArNH_(2)` during diazotization of `ArNH_(2)` we use an excess of mineral acid As result most of `ArNH_(2)` is converted to `Aroverset(+)NH_(3)` which does not couple
.