Hydrochloric acid, impurities properties

T. Thomson 15 thought that he had obtained what he called a carburet of phosphorus— or carbon phosphide—when impure calcium phosphide is decomposed by water, and the lime removed by hydrochloric acid the residual carbon phosphide was collected on a filter and quickly washed. It was said to be a brownish-yellow, soft, tasteless, inodorous, infusible powder, which suffers no alteration in dry air below 100°, but takes fire at a red-heat when the phosphorus bums to phosphoric acid while the carbon is not changed. It attacks moisture from the air, forming a hydrocarbon, and carbon dioxide. The properties of the alleged phosphide correspond with those of a mixture of carbon and phosphoric acid with perhaps a small proportion of phosphorus. J. J. Berzelius said that a similar... 

Ceric oxide, Ce02, is prepared by igniting cerium or any cerous or ceric salt of an oxy-acid. Its density depends upon the method of preparation. The color is the subject of much discussion.) We would expect a white oxide like zirconia and thoria. White oxides have been prepared, but Brauner has shown that such ceria contains impurities. As usually obtained ceria has a pale yellow color. It volatilizes without melting or decomposition at about 1900°. Besides being a weak base it shows slight evidence of faintly acidic properties. While pure ceria is insoluble in nitric or hydrochloric acids, a mixture of rare earth oxides dissolves readily... 

Pure aldrin is a white crystalline compound the technical product is a waxy, brown substance, containing about 78-95% of aldrin in addition to other products, some of which have insecticidal properties. One part of the impurities decomposes during storage by elimination of hydrochloric acid. This decomposition can be inhibited by using acid inhibitors, for example epichlorohydrin, as stabiliser. 

Acid-activated clay - This is calcium bentonite that has been treated with sulfinic or hydrochloric acid to exchange calcium widi hydrogen ions, to dissolve carbonate impurities, to leach some tetrahedral aluminum and octahedral magnesium, aluminum, and iron, and to delaminate the edges of the stacks of clay platelets. The overall effect is to increase porosity and surface area and, thereby, the cl s absorptive properties. This type of bentonite is used primarily to decolorize and deodorize petroleum and edible oils. 

Y Picoline. Commercially pure y-picoline contains )S-picoline and 2 6-lutidine and sometimes traces of non-basic impurities (aromatic hydrocarbons) which cannot be separated by fractionation. The non-basic impurities are removed by steam distillation of the base in dilute hydrochloric or sulphuric acid solution (for details, see under a Picoline). The impure y-picoline is converted into the zinc chloride complexes of the component bases the 2 6-lutidine - ZnClj complex is the least stable and upon steam distillation of the mixture of addition compounds suspended in water, 2 6-lutidine passes over flrst. The complete separation of the 2 6-lutidine may be detected by a determination of the density and the refractive index of the dry recovered base at varioiu stages of the steam distillation. The physical properties are —... 

Commercial products contain chiefly carbon, but substantial amount of mineral substances (e.g. metals and silicon) is always occluded in the pores. These impurities are difficult to remove (especially from micropores), and even multiple cycles of washing with hot hydrochloric and hydrofluoric acid or mixture thereof leave substantial amounts of impurities in the pores. Inorganic impurities affect the sorption properties of activated carbons. Therefore the elemental analysis of the activated carbons is often reported as the part of their characterization. In many studies the commercial materials were purified (usually using HCI and HF), but other authors did not pay attention to possible role of mineral impurities. Certainly the results obtained with relatively large and unknown amount of impurities are of limited significance. 

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