Identify the major product 'B' in the given reaction sequence.

Step-by-step solution

The given reaction sequence involves two steps: First, p -toluidine reacts with NaNO ₂ and HCl at 273-278 K to undergo diazotization. The primary amine group ( - NH ₂ ) is converted into a diazonium salt ( - N ₂^+ Cl ^- ), forming p -toluenediazonium chloride as product A. Next, product A is treated with hypophosphorous acid ( H ₃ PO ₂ ) and water. H ₃ PO ₂ acts as a mild reducing agent, replacing the diazonium group with a hydrogen atom. The reaction proceeds as follows: Ar - N ₂^+ Cl ^- + H ₃ PO ₂ + H ₂ O Ar - H