The reaction of benzene diazonium fluoroborate with aqueous sodium nitrite in the presence of copper leads to the formation of nitrobenzene. This reaction is a typical example of the Sandmeyer reaction, where a diazonium salt undergoes a substitution reaction in the presence of copper and sodium nitrite, forming a nitro group on the benzene ring.
The correct option is (E) : nitrobenzene
The reaction involves benzene diazonium fluoroborate (\(C_6H_5N_2BF_4\)) reacting with aqueous sodium nitrite (NaNO2) solution in the presence of copper.
This is a variation of the Sandmeyer reaction. The diazonium salt is converted to a nitro group (\(-NO_2\)). The reaction proceeds as follows:
\(C_6H_5N_2BF_4 + NaNO_2 \xrightarrow{Cu} C_6H_5NO_2 + N_2 + NaBF_4\)
Benzene diazonium fluoroborate reacts with sodium nitrite in the presence of copper to form nitrobenzene.
Therefore, the answer is nitrobenzene.