XI.—On some remarkable circumstances tending to disguise the presence of various acids and bases in chemical analysis

Spiller, John

doi:10.1039/qj8581000110

Cited by 2 publications

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“…Logic P(mm.) = 9.33902 -(1864.8/ ) (1) The latent heat of sublimation, calculated by the approximate Clapeyron equation:…”

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THE VAPOR PRESSURES OF SOLID AND LIQUID HYDROGEN CYANIDE¹

Perry¹,

Porter²

1926

J. Am. Chem. Soc.

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There is but one investigation on the vapor pressure of pure liquid hydrogen cyanide recorded in the literature,2 with the exception of a few isolated attempts at determining the boiling point. A painstaking search failed to reveal any references on the vapor pressures of solid hydrogen cyanide. It was to supply this deficiency of data that the following investigation was begun.Experimental Part Preparation of Hydrogen Cyanide.-The hydrogen cyanide was prepared by dropping dil. (1 :1) sulfuric acid upon pulverized potassium cyanide. The hydrogen cyanide evolved was passed through two tubes of phosphorus pentoxide and then condensed in a glass bulb immersed in liquid air. The hydrogen cyanide was melted and frozen and any permanent gas pumped off until there was no residual pressure in liquid air. The material was then fractionated several times until, before and after a fractionation, it showed no change in vapor pressure at the ice point. Since the pressure at the ice point is over 260 mm., this was very good evidence as to the purity of the hydrogen cyanide.Apparatus.-The temperature measurements were obtained with a spade-type, platinum-resistance thermometer which had been carefully calibrated at the ice and steam points, and the boiling points of naphthasne and oxygen. The Henning equation,3 evaluated from these points,

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“…Logic P(mm.) = 9.33902 -(1864.8/ ) (1) The latent heat of sublimation, calculated by the approximate Clapeyron equation:…”

mentioning

confidence: 99%