Free hydrochloric acid

The conversion of the diazoaminobenzene into aminoazobenzene is promoted by the addition of aniline hydrochloride even more readily than by that of free hydrochloric acid. The aniline hydrochloride dissociates in solution giving hydrochloric acid and aniline the former promotes the formation of the above equilibrium, and the latter by increasing the active mass of the free aniline further accelerates the condensation to aminoazobenzene,... 

The aqueous portion from which the cake of acid is removed contains free hydrochloric acid, potassium chloride, and glyceiol. The latter may be obtained by evapoiating to dryness on the water-bath, and extracting the residue with small quantities of alcohol, which dissolves out the glycerol. On evaporating the alcohol impure glycerol is left. 

The rate of evaporation is greatly accelerated by allowing a stream of air to blow across the surface of the hot liquid. It is advantageous for the evaporation to proceed as far as possible in order to remove most of the free hydrochloric acid, and no harm is done if it continues until the solution turns to a semi-solid mass of crystals. 

Flydrochloric acid regeneration. This process is used to treat the spent pickle liquor containing free hydrochloric acid, ferrous chloride, and water that is obtained from steel finishing operations. The liquor is concentrated by heating to remove some of the water, followed by thermal decomposition in a roaster at temperatures (925 to 1050°C) sufficient for complete evaporation of water and decomposition of ferrous chloride into iron oxide (ferric oxide, Fe203) and hydrogen chloride (HC1) gas.19 The iron oxide is separated for offsite recovery or... 

Salt-free hydrochloric acid hydrolyzate of casein, Baltimore Biological Laboratory Inc., Baltimore, Maryland. These casein hydrolyzates can be substituted by Casamino acid (Difco), enzymatically hydrolyzed casein or acid-hydrolyzed casein. 

Is unstable under certain conditions. For example, this popular Industrial refrigerant and aerosol, In the presence of moisture, will react with steel or aluminum forming free hydrochloric acid As a result, efforts are made to maintain anhydrous conditions or provide acid scavengers. Although not widely known. Freon 11 will react with primacy and secondary alcohols Including polyols to liberate aldehydes, ketones and hydrochloric acid All the above... 

This reaction Is not a widely known text book reaction. In fact. It was only found In the patent literature (4 ). However, this reaction explains the evidence of free hydrochloric acid. Since a carbonyl group, e.g., aldehyde, was generated by the above reaction, this group should be observable In the IR. Subsequent IR scans of the aged polyol revealed formation of a carbonyl at about 5.8 microns. Unaged polyol shows negligible carbonyl formation. 

Ddute sulfuric acid has no effect on the metal nor does air-free hydrochloric acid. But dilute nitric acid dissolves the metal excess mercury in cold dilute acid yields mercury(l) nitrate, the dihydrate Hg2(N03)2 2H20 separating out on crystaUization. Mercury dissolves in aqua regia forming mercury (11) nitrate. 

William Prout detects free hydrochloric acid in the stomach. Berzelius isolates amorphous silicon. 

Owing to the presence of small quantities of free hydrochloric acid in the crude product, the above procedures are applicable to recrystallized specimens only. 

When treated with water, bromine and iodine are set free hydrochloric acid liberates iodine sodium or ammonium hydroxides give a black precipitate of nitrogen iodide, and the mother liquid liberates bromine when treated with hydrochloric acid. Sulphurous acid gives hydrobromic and hydriodic acids. F. Ephraim. found the dissociation press, of NI IB to be 65 mm. at 107° 204 mm. at 134° 465 mm. at 154° and 640 mm. at 161°. 

The trithionates may be quantitatively precipitated by boiling for one hour with a mixture of copper sulphate and barium chloride solutions containing free hydrochloric acid 4... 

The authors drew attention to the induction period noticeable in both types of samples of pure ammonium nitrate and those with ammonium chloride. The time, length and character of the induction period does not seem to depend on the concentration of ammonium chloride in the samples. After the induction period the decomposition of ammonium nitrate with ammonium chloride becomes faster than that of the pure substance. Guiochon and L. Jacqud found that the samples became acid during the induction period. Free nitric acid, and in the samples with ammonium chloride free hydrochloric acid (and subsequently chlorine) are formed. By adding nitric acid or chlorine to the samples, a considerable reduction or suppression of the induction period was achieved. 

Reactions of tin(H) ions A 0-25m solution of tin(II) chloride, SnCl2.2H20, can be used for studying these reactions. The solution should contain at least 4 per cent free hydrochloric acid (100 ml concentrated HCI per litre). 

Neutral FeCl3 solution is prepared by adding dilute ammonia solution dropwise to the side-shelf FeCl3 solution until a slight permanent precipitate forms this is filtered off. The side-shelf reagent usually contains excess free hydrochloric acid added during its preparation to produce a clear solution the free acid leads to incomplete precipitation. 

The bench reagent contains free hydrochloric acid add dilute ammonia solution until a precipitate just forms, filter and use the filtrate for the test. The filtrate is sometimes termed neutral FeCl3 solution.)... 

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