Manual of chemical analysis as applied to the examination of medicinal chemicals : a guide for the determination of their identity and quality, and for the determination of their identity and quality, and for the detection of impurities and adulterations : for the use of pharmaceutists, physicians, druggists, and manufacturing chemists, and of pharmaceutical and medical students . to form a soluble com-pound with alkaline , therefore, the officinalhydrocyanic acid is convert-ed into sodium or potassiumcyanide by addition of sodi-um or potassium hydrate, nopermanent precipitate wil
Manual of chemical analysis as applied to the examination of medicinal chemicals : a guide for the determination of their identity and quality, and for the determination of their identity and quality, and for the detection of impurities and adulterations : for the use of pharmaceutists, physicians, druggists, and manufacturing chemists, and of pharmaceutical and medical students . to form a soluble com-pound with alkaline , therefore, the officinalhydrocyanic acid is convert-ed into sodium or potassiumcyanide by addition of sodi-um or potassium hydrate, nopermanent precipitate willappear, upon the addition ofnitrate of silver, until morethan sufficient cyanide of sil-ver is produced to form thesoluble compound. I. One hundred grains ofthe acid are completely pre-cipitated by a solution of ar-gentic nitrate. Then two fil-ters of exactly the same size and paper are cut; through the one the liquid is filtered,the precipitate washed, and then both the empty filter andthe one containing the argentic cyanide are dried, at a heatnot exceeding 100° C. When the weight of the latter filterremains constant, both filters are weighed, the empty one serv-ing as a counterpoise of the one containing the precipitate;the excess of weight of the latter is argentic cyanide, of which— 10 grains represent per cent, anhydrous hydrocyanic acid, 11 *. Fn. 33. 90 MANUAL OF CHEMICAL ANALYSIS. II. Twenty-seven grammes of the diluted hydrocyanic acidare converted into sodium cyanide, by adding solution of sodiumhydrate until, after stirring, litmus-paper shows that the liquidhas a slightly alkaline reaction. The test-solution of argenticnitrate is then allowed to flow in gradually (Fig. 33), until,after agitation, a slight permanent turbidity remains. Whenthis occurs, the quantity of argentic nitrate added representsexactly half the amount of hydrocyanic acid present in thediluted acid, and the quantity of acid indicated denotes, there-fore, when doubled, the
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Keywords: ., bookcentury1, bookdecade1870, booksubjectpharmaceuticalchemistry
