JEE Advanced Chemistry Question (2022) — Solution

Step-by-step solution

First step of the reaction involves reduction of nitro group to primary amine this can be done using Sn in presence of HCl or H 2 /Pd, but aromatic nitro compounds on reaction with LiAlH 4 produces azo products.  Second step of the reaction involves diazotization, which involves the use of HNO 2  (or) NaNO 2  in HCl as the reagent ,Para toluene diazonium chloride formed is formed which on hydrolysis produces para-cresol. And Para toluene diazonium chloride can be converted to benzoic acid by using  H 3 PO 2   or   C 2 H 5 OH  followed by reaction with  KMnO 4   in   alkaline   medium → P may be → H 2 Pd , ethanol;  Sn HCl → R may be  → NaNO 2 / HCl ; HNO 2 → U  may be → (i) H 3 PO 2 , (ii) KMnO 4 - KOH , Δ or (i) CH 3 - CH 2 - OH , (ii)  KMnO 4 - KOH , Δ