CBSE Class 12 · 2003 · Foreign · Compounds Containing NitrogenVery Short Answer

How is Orange-I prepared?

Answer: Couple diazotised sulphanilic acid with 1-naphthol in mildly alkaline medium → the azo dye Orange-I.

Solution

Diazotise sulphanilic acid (NaNO

_{2}

/HCl, 273–278 K), then pour into alkaline 1-naphthol:

p - H O_{3} S - C_{6} H_{4} - N_{2}^{+} + 1 - naphthol O H^{-} Orange - I

(the azo –N=N– links the two rings; coupling occurs at the naphthol's activated position).

CBSE Class 12 Board · 2003 · Foreign · Subjective