Ammonium cyanide, dissociation

Ammonium cyanide forms colourless cubes, readily volatilized and completely dissociated at comparatively low temperatures.14 Its heat of formation from diamond, hydrogen, and nitrogen is 3-2 Cal.15 It dissolves readily in both water and alcohol, the salt being extensively dissociated in aqueous solution. It is extremely poisonous. 

Ammonium cyanide.— Isambert has likewise studied the dissociation of certain solid non-volatile substances, formed by... 

Isambert has verified this relation in stud3dng the dissociation of ammonia bisulphydrate and of the bromhydrate of phos-phoretted hydrogen he has made an especially careful verification for the case of ammonium cyanide in the presence of an excess of ammonia gas. 

The measurement of , joined to the knowledge of (o, allows deriving from equation (12) a first value of Pji the measurement of the dissociation tension x of ammonium cyanide in an enclosure empty at first allows finding from equation (13) another vale of P29 which we shall denote by p/ if the law we are concerned with is true, the two pressures pj, p, should be equal to each other. 

Isambert has also studied the dissociation of ammonium cyanide... 

The ammonium salts are, in practice, divided into (a) volatile, (/>) fixed. The volatile ammonium salts on boiling with water dissociate, evolving ammonia. The chief volatile salts are —Ammonium carbonate (NHjl.XX ammonium sulphide (NH4).,S and NH4HS ammonium cyanide, NH4CN. 

The a-aminonitrile can also be obtained by the treatment of the aldehyde with HCN followed by reaction of the formed cyanohydrin with ammonia. This method is known as Erlenmeyer modification. A more convenient route is to treat the aldehyde in one step with ammonium chloride and sodium cyanide (this mixture is equivalent to ammonium cyanide, which in turn dissociate into ammonia and HCN). This procedure is referred to as the Zelinsky-Stadnikott modification. The final step is the hydrolysis of the intermediate a-aminonitrile under acidic or basic conditions. 

Procedure II. A drop of the test solution is precipitated with the reagent, either on a spot plate or on filter paper, and then a few drops of dilute hydrochloric acid or ammonium chloride are added. The mercury compound dissolves while the red silver precipitate remains. Procedure II is recommended when copper as well as mercury is present, since the cuprous cyanide is sufficiently dissociated (when potassium cyanide is used) to react with the reagent to give a red insoluble cuprous salt, which resembles the silver compound. 

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