An organic compound 'A' ( C ₈ H ₉ NO ) on treatment with Br ₂ and aqueous NaOH gives a compound 'B'. Compound 'B' on treatment with NaNO ₂ and HCl at 0-5^ C followed by warming with water produces compound 'C'. When 'C' is treated with bromine water, it forms a white precipitate of a tribromo derivative 'D'. The structure of 'A' is:

Step-by-step solution

Compound 'A' ( C ₈ H ₉ NO ) reacts with Br ₂ and aqueous NaOH to give 'B'. This is the Hoffmann bromamide degradation, indicating 'A' is a primary amide and 'B' is a primary amine with one carbon less ( C ₇ H ₉ N ). Since 'A' has a benzene ring (from its degree of unsaturation), 'A' is a methylbenzamide and 'B' is a methylaniline (toluidine). Compound 'B' undergoes diazotization with NaNO ₂ and HCl followed by hydrolysis with warm water to form a phenol derivative 'C' ( C ₇ H ₈ O ), which is a cresol (methylphenol)