question_answer 100)

  Predict the reagent or the product in the following reaction sequence.  

Answer:

                  (i) Since the reagent (1) reduces -  to - , therefore, I is either Sn/HCl or Fe/HCl. (ii) Since p-methylacetanilide on treatment with a mixture of cone.  + cone.  gives compound (2), therefore, compound (2) must be 2-nitro-4-methylacetanilide. (iii) Since reagent (3) brings about hydrolysis of  to therefore, it must be aqueous acid, i.e., . (iv) Since product (4) is obtained upon treatment of 1° aromatic amine with , therefore, compound (4) must be a diazonium salt   2-Nitro-4= methylbenzenediazonium chloride (v) Since reagent (5) brings about the substitution of diazo  group by H or brings about reduction of diazonium chloride, therefore, it must be aqueous hypophosphorus acid, i.e., .