Prussic acid HCN

Segregation is practised to allow for housekeeping, construction and maintenance requirements and to reduce the risk of an accident resulting in a domino effect , e.g. from a fire, explosion or toxic release. For very toxic substances, e.g. prussic acid (HCN) or tetraethyl lead, this may involve isolating the entire manufacturing operation in a separate unoccupied building or sealed-off area. 

Gay-Lussac found that reaction of prussic acid (HCN) with chlorine gas produced cyanogen chloride (CICN). How could an electronegative element replace an electropositive one ... 

Hydrogen cyanide (hydrocyanic acid, prussic acid, HCN [CAS 74-90-81) A rapidly acting, potent metabolic asphyxiant that inhibits cytochrome oxidase and stops cellular respiration. See also p 177. 4.7 ppm (C), S 50 ppm ERPG-2 10 ppm ERPG-3 25 ppm 4 4 2 (vapors extremely toxic) Colorless to pale blue liquid or colorless gas with a sweet, bitter almond smell that is an inadequate warning property even for those sensitive to it. Vapor pressure is 620 mm Hg at 20 C (68°F). Cyanide salts will release HCN gas with exposure to acids or heat. 

Regulatory Status. Leaves approved for food as natural flavoring substance provided prussic acid (HCN) does not exceed 25 ppm ( 172.510). 

Under the name prussic acid, HCN has been used as a killing agent in whaling harpoons. 

Other impurities vary widely. One common impurity is water, which can be removed by either absorption or adsorption. Another is ammonia (NH3), which is basic, rather than acidic. Sulfur trioxide (SO3), prussic acid (HCN), and nitrogen oxides (NO, ) are of concern because of their high chemical reactivity. Oxygen must be removed from some reagent streams, and nitrogen can be absorbed to upgrade natural gas. 

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