The product (P) formed from the following multistep reaction is:

Step (i): Bromination ($$\text{Br}_2$$)

When 4-nitrotoluene reacts with $$\text{Br}_2$$, electrophilic aromatic substitution occurs. We must look at the directing influence of both groups to determine where the bromine atom ($$\text{-Br}$$) will attach:

• The $$\text{-CH}_3$$ group directs incoming electrophiles to its ortho positions (positions 2 and 6 relative to itself).
• The $$\text{-NO}_2$$ group directs incoming electrophiles to its meta positions (which also happen to be positions 2 and 6 relative to the $$\text{-CH}_3$$ group).

Because both groups reinforce each other, the bromine atom is introduced ortho to the methyl group and meta to the nitro group.

$$\text{Intermediate 1} = \text{2-bromo-4-nitrotoluene}$$

Step (ii): Reduction ($$\text{H}_2 / \text{Pd}$$)

Catalytic hydrogenation using hydrogen gas over a palladium catalyst ($$\text{H}_2/\text{Pd}$$) selectively reduces the strongly electrophilic nitro group ($$\text{-NO}_2$$) into an amino group ($$\text{-NH}_2$$). The ring-bound bromine and methyl groups remain unaffected under these typical conditions.

$$\text{Intermediate 2} = \text{3-bromo-4-methylaniline}$$

Step (iii): Diazotization ($$\text{NaNO}_2, \text{HCl}, 0^\circ\text{C}$$)

Reacting a primary aromatic amine ($$\text{-NH}_2$$) with nitrous acid (generated in situ from $$\text{NaNO}_2$$ and $$\text{HCl}$$) at a low temperature ($$0^\circ\text{C} - 5^\circ\text{C}$$) converts the amino group into a highly reactive diazonium salt group ($$\text{-N}_2^+\text{Cl}^-$$).

$$\text{Intermediate 3} = \text{3-bromo-4-methylbenzenediazonium chloride}$$

Step (iv): Deamination ($$\text{H}_3\text{PO}_2$$)

Hypophosphorous acid ($$\text{H}_3\text{PO}_2$$) acts as a mild reducing agent that replaces the diazonium group ($$\text{-N}_2^+$$) with a hydrogen atom ($$\text{-H}$$), releasing nitrogen gas ($$\text{N}_2$$). This effectively removes the original functional group at that position entirely.

Therefore, the final product (P) is 2-bromotoluene (also called o-bromotoluene).