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Aniline (C) undergoes diazotisation: C -[NaNO2 + HCl, 0-5 deg C]-> X -[compound P (an activated aromatic ring), pH = 4-5]-> Y. Select the correct statement(s).

1. (A) Y is a coloured compound
2. (B) X to Y is a coupling reaction
3. (C) The colour of Y is due to extended conjugation
4. (D) X acts as an electrophile during the conversion of X to Y

Correct answer: (A) Y is a coloured compound

Solution

Aniline (C) is diazotised to give benzenediazonium chloride (X). At pH 4-5, X couples with compound P (e.g., phenol or naphthol) via electrophilic aromatic substitution to form Y, an azo dye. Y is coloured (A correct), the reaction is azo coupling (B correct), colour arises from extended conjugation through -N=N- (C correct), and X (diazonium) acts as electrophile (D correct). All four statements are correct.

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