How can the following conversion be effected ?
(a) Nitrobenzene to anisole
(b) Chloro benzene to phenyl hydrazine
(c) Aniline to benzoic acid
(d) Benzene diazonium chloride to Ethyl benzene

Explanation

`C_(6)H_(5)NO_(2) overset(Sn//HCl)rarr C_(6)H_(5)NH_(2) overset(HNO_(2))underset(HCl)rarr C_(6)H_(5)N_(2)Cl overset(CH_(3)OH) rarr C_(6)H_(5)OCH_(3)`
`C_(6)H_(5)Cl overset(NH_(3))underset(HCl)rarr C_(6)H_(5)NH_(2) overset(HNO_(2))underset(HCl)rarr C_(6)H_(5)N_(2)Cl overset(Sn//HCl)rarr C_(6)H_(5)NHNH_(2)`
`C_(6)H_(5)NH_(2) overset(HNO_(2))underset(HCl)rarr C_(6)H_(5)N_(2)Cl overset(KCN) underset(Cu_(2)(CN)_(2))rarr C_(6)H_(5)CN overset(H_(3)O^(+))rarr C_(6)H_(5)COOH`
`C_(6)H_(5)N_(2)Cl overset(HBr) underset(Cu_(2)Br_(2))rarr C_(6)H_(5)Br underset(underset("dry ether")(C_(2)H_(5)Br))overset(Na)rarr C_(6)H_(5)-C_(2)H_(5)`