How is nitrobenzene converted to aniline?

The conversion of nitrobenzene to aniline is done by reduction of the nitro group (–NO₂) to an amino group (–NH₂), using reducing agents such as tin (Sn) with hydrochloric acid (HCl), or catalytic hydrogenation.

Step-by-step explanation:

• The starting compound: Nitrobenzene (C₆H₅–NO₂).
• Reduction: The nitro group is reduced to an amino group. Typical reagents include Sn + HCl, Fe + HCl, or catalytic hydrogenation (H₂ with Ni, Pt or Pd catalyst).
• When using Sn + HCl: Nitrobenzene + 3 Sn + 14 HCl → Aniline (C₆H₅–NH₂) + 3 SnCl₄ + 2 H₂O.
• After reduction, the reaction mixture is neutralised (typically by adding base) to isolate aniline.
• Reaction condition must be controlled (temperature, catalyst) to prevent over-reduction or side-products.

Thus: nitrobenzene → (reduction) → aniline.