Question 8

Analysis of products:

1. Aniline is acetylated to acetanilide, which then undergoes para-nitration to give $P$ (p-nitroacetanilide). Thus, $P$ is a mononitro compound, making (C) incorrect.
2. $P$ is hydrolyzed and diazotized to give $Q$ (p-nitrobenzenediazonium chloride).
3. Cumene is converted to phenol via the cumene hydroperoxide process. Phenol then reacts with $NaOH/CO_2$ followed by $H_3O^+$ (Kolbe-Schmitt reaction) to give $S$ (salicylic acid).
4. $Q$ (diazonium salt) couples with $S$ (phenolic compound) in aqueous $NaOH$ to form $T$, which is an azo dye. Azo dyes are conjugated and thus coloured. This makes (D) correct.
5. (A) is incorrect because diazonium salts ($Q$) react with ethanol to undergo reduction, forming nitrobenzene and acetaldehyde, not an aromatic aldehyde.
6. (B) is correct because $S$ (salicylic acid) contains a phenolic $-OH$ group, which can react with phthalic anhydride in the presence of $H_2SO_4$ to give a positive phthalein dye test (similar to phenol giving phenolphthalein).