REACTIONS AND IDENTIFICATION 407 E. Treat with 10% aqueous NaOH solution, then heat (p. 329). (a) Dissolves easily in cold NaOH solution although insoluble in cold water. Some phenols*; aromatic carboxylic acids; some amino-acids; uric acid. (b) Dissolves easily in cold NaOH solution (although only slightly soluble in cold water), at the same time forming deep yellow or orange alkaline solution. Nitrophenols. (Salicylaldehyde gives a yellow coloration in the cold: m-dinitrobenzene gives a reddish-brown coloration on wanning.) (c) Dissolves easily, giving yellow solution which rapidly darkens on shaking. Benzoquinone. Polyhydric phenols, e.g., resorcinol, rapidly darken. ( d ) Ammonia evolved in the cold.\ Ammonium salts. (e) Ammonia evolved on heating. Amides, irnides, nitriles (slowly). (/) Brown resinous product formed. Aliphatic aldehydes (except formaldehyde); carbohydrates and soluble starch (sucrose and ordinary starch only faintly coloured). (g) Reacts slowly on heating without evolution of gas.
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