# Reaction mechanism for reduction of nitrobenzene to aniline in catalytic and acidic media

Can anyone explain the reaction mechanism of the two reactions given below?

They are the conversion of nitrobenzene to aniline in catalytic ($\ce{H2/Pd}$ in ethanol) and acidic ($\ce{Sn/HCl}$ or $\ce{Fe/HCl}$) mediums respectively.

$$\ce{Ar-NO2 ->[\ce{H2/Pd}][\ce{EtOH}] Ar-NH2}$$
$$\ce{Ar-NO2 ->[\ce{Sn + HCl} \text{ or } \ce{Fe + HCl}] Ar-NH2}$$

• What are your own thoughts on the matter? Do you have done any research or have any clue what might happen? – Philipp Jul 30 '14 at 16:22