Azo dye formation for aromatic primary amines:.They react with nitrous acid to yield alcohols and nitrogen (causes rapid foaming). Phenols react with benzoyl chloride in presence of NaOH, to form esters.Īt low temperature (0-5 oC) aromatic primary amines dissolved in strong acids (HCl & H 2SO 4) reacts with nitrous acid (NaNO 2 +HCl) to form water soluble diazonium salts.Īliphatic primary amines do not form stable diazonium salts under similar condition.
These reactions are called coupling reactions. phenol & resorcinol - violet colour, catechol-green etc.Īryldiazonium salts react with aromatic rings of phenols to form highly coloured azo compounds. Phenol form characteristic coloured iron complexes when treated with neutral ferric chloride solution.
This biuret in alkaline medium gives a violet colour with a drop of copper sulphate solution. When aliphatic diamide is heated at a temperature above its melting point, ammonia is evolved and crystalline biuret is formed. The soluble sodium salt of aromatic acid formed from aromatic amides upon hydrolysis is regenerated as white precipitate in acidic medium. Alkaline hydrolysis of aromatic amides to aromatic acid:.The gas can be tested by a moist red litmus paper which is then turned blue. Systematically identify the functional groups in the given organic compound and perform the confirmatory tests after identifying the functional groups.Īmides are decomposed by NaOH to evolve ammonia.