In the Sandmeyer reaction, benzenediazonium chloride reacts with $CuCl$ on the lab bench to give:
APhenol, by replacement of the diazonium with OH always
BBenzene, by simple loss of nitrogen gas as the only step
CAniline, by reduction of the diazonium with Cu metal here
DChlorobenzene, by replacement of $N_2^+$ with $Cl$ in the ring
Answer & Solution
Correct answer: D. Chlorobenzene, by replacement of $N_2^+$ with $Cl$ in the ring
Sandmeyer: $ArN_2^+ + CuCl \to ArCl + N_2 + Cu^+$; gives chlorobenzene.