To obtain the best yield of the azo dye when benzenediazonium chloride is coupled with phenol, the pH of the reaction medium should be maintained at

Step-by-step solution

The coupling reaction of benzenediazonium chloride with phenol is an electrophilic aromatic substitution where the diazonium ion acts as the electrophile. Phenol is converted into the phenoxide ion in an alkaline medium, which is a much stronger nucleophile and highly reactive towards electrophilic substitution. However, if the medium is too highly alkaline (pH > 10 ), the diazonium ion reacts with hydroxide ions to form diazohydroxide and subsequently the diazotate ion, which are not electrophilic and do not under