Step 1: Nature of the diazonium salt.
Benzene diazonium chloride is a weak electrophile and reacts with electron rich aromatic rings in a coupling reaction.
Step 2: Role of phenol and the basic medium.
Phenol is electron rich. In weakly basic medium part of it changes to the even more reactive phenoxide ion.
Step 3: The coupling.
The diazonium ion attacks the phenol ring at the para position (which is most reactive and least crowded). This is azo coupling.
Step 4: The product.
A \(-N=N-\) bridge joins the two rings, giving p-hydroxyazobenzene, an orange dye.
Step 5: Conclusion.
The product of the reaction is p-hydroxyazobenzene.
Answer: p-hydroxyazobenzene.