A given nitrogen-containing aromatic compound 'A' reacts with Sn/HCl, followed by HNO2 to give an unstable compound 'B'. 'B', on treatment with phenol, forms a beautiful coloured compound 'C' with the molecular formula C12H10N2O. The structure of compound 'A' is
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Answer
(2) [figure]
Solution
'C' ( C12H10N2O) is the orange azo dye p-hydroxyazobenzene, formed by coupling of benzenediazonium chloride with phenol.
'B' is benzenediazonium chloride (unstable), formed from aniline by diazotisation.
Aniline is formed by reduction of nitrobenzene with Sn/HCl.
C6H5NO2 Sn/HCl C6H5NH2 NaNO2/HCl, 273-278 K C6H5N2+Cl-
C6H5N2+Cl- + C6H5OH OH- p-HO-C6H4-N=N-C6H5 (C12H10N2O)
'A' is nitrobenzene.
Answer: (2)