How is nitrobenzene converted to benzoic acid?

Explanation

Nitrobenzene is converted to aniline which on diazotisation gives benzene diazonium chloride. This on treating with potassium cyanide in the presence of cuprous cataylst gives benzonitrile and it gives benzoic acid on hydrolysis.
`C_(6)H_(5)NO_(2) underset(HCl)overset(Sn)rarr C_(6)H_(5)NH_(2) underset(HCl)overset(NaNO_(2))rarr C_(6)H_(5)N = NCl underset(CuCN)overset(KCN)rarr C_(6)H_(5)CN overset(H_(3)O^(+))rarr C_(6)H_(5)COOH`