§ 3. REAGENTS. 11 



e. Ammonic hydrate.— NH^HO. Ammonia JVJI^.— 



This should be colorless, and leave no residue when evap- 

 orated in a watch-glass : after dilution with its volume of 

 water, it should give no very marked turbidity with lime- 

 water, and, after supersaturation with nitric acid in slight 

 excess, it should give no precipitate or color with argentic 

 nitrate, baric chloride, or ammonic sulphide. 



/. Ammonic molybdate. — (NHJ3IoO^. (Molybdate 



of ammonia. NH^OjMoOg.) — Dissolve 1 part of molyb- 

 dic acid in 8 parts of ammonia- water, pour the solution 

 into 20 parts by weight of nitric acid (Sp. Gr.=1.2), let 

 the mixture stand several days in a warm place, and 

 decant the clear liquid for use. When moderately heated 

 with excess of nitric acid, it should give no yellow pre- 

 cipitate. 



^. Ammonic nitrate. — NH^ISr03. (titrate of ammonia. 

 NH^O, NO^.) — This should give no reaction Avith baric 

 chloride or argentic nitrate, and should be completely 

 volatilized when heated. 



A. Ammonic oxalate. — (NHJ.C^O^. (Oxalate of am- 

 monia. 2X11^0,0^05.) — This should be completely vola- 

 tiUzed by heat, and should give no reaction with hydro- 

 sulphuric acid, or ammonic sulphide, or with baric chloride 

 in a solution acidified with hydrochloric acid. Dissolve 

 in 24 parts of Avater. 



^. Ammonic sulphate. — (XH,)„SO^. (Sulphate of am- 

 monia. NH^OjSOg.) — This may be readily prepared by 

 neutralizing ammonic hydrate with dilute sulphuric acid. 



7c. Ammonic Sulphide. — (NHJ^S. (Sulphide of am- 

 monium. KH^S.) — Conduct sulphuretted hydrogen (§ 1, 

 c7) into 3 parts of ammonic hydrate as long as the gas 

 is absorbed, and add 2 parts of fresh ammonic hydrate. 

 The reagent should evolve sulphuretted hydrogen freely 

 w^hen mixed with strong acids, and should give at least 

 only a white precipitate with them ; it should give no re- 



