Answer: The byproduct is mostly p-cresol, which is p-methylphenol.
Step-by-step explanation:
Because of the many hydrolysis of the diazonium salts that would occur since the temperature of the reaction is greater than 0-5°C, there would be the formation of p-cresol as one of the byproducts, and it is of the highest yield among the three byproducts formed.
Simple Explanation of the Reaction Process:
The process starts from the diazotization of p-toluidine to form diazonium salt as an intermediate.
The reaction would then be quenched by urea and what follows subsequently is the hydrolysis of the diazonium salts to give p-cresol in high yield.