Introducing a fluoride group into the benzene ring using diazonium salts involves the Balz-Schiemann reaction. In this process, the diazonium salt reacts with hydrogen fluoride (HF) or a fluoride salt (e.g., KF) under specific conditions. The resulting product is an aryl fluoride. For instance, treating benzenediazonium chloride with potassium fluoride (KF) leads to the replacement of the diazo group with a fluorine atom, yielding fluorobenzene. The reaction is a valuable method for synthesizing aryl fluorides, which find applications in medicinal chemistry, materials science, and organic electronics.