Hydrochloric acid solution releases

Accidental addition of 6500 1 of cone, hydrochloric acid to a bulk sulfuric acid storage tank released sufficient hydrogen chloride gas by dehydration to cause the tank to burst violently [1], Complete dehydration of hydrochloric acid solution releases some 250 volumes of gas. A laboratory apparatus for effecting this safely has been described [2], which avoids the possibility of layer formation in unstirred flask generators [3],... 

Loading the sample in nitric acid solution, the tetravalent actinides are strongly retained along with hexavalent uranium. However, trivalent actinides like Am(III) and Pu(III) are not retained from nitric acid solutions (unlike TRU-Resin). Pu retained as Pu(IV) can be removed from the column by reducing it to Pu(III). Tetravalent actinides and U(VI) are also retained in strong hydrochloric acid solution, with retention sharply dropping off as hydrochloric acid concentrations decrease (see Figure 9.12). Th(IV) is less retained in hydrochloric acid solutions than U(VI). Actinides retained on UTEVA-Resin from nitric acid solutions can be released with diluted nitric acid or low hydrochloric acid concentrations. 

Derivation Action of hydrogen chloride on antimony-metal compounds such as Zn3Sb2 also released by reduction of antimony compounds in hydrochloric acid solutions with zinc or other reducing metal. 

The acid solution of the amphetamine is now made alkaline to liberate the free base for distilling. To do this, lye is added to the acid solution in the 2000 ml flask. Assuming the use of about 1200 ml of 15% hydrochloric acid solution, one 12 oz. can of lye does the job. The mixture is first swirled to release heat, then shaken vigorously for five minutes. I cannot emphasize enough the importance of vigorous and prolonged shaking here because the amphetamine base initially formed tends to dissolve... 

Chemical changes can result in the release or absorption of heat, as illustrated in Figure 5.8. They can also cause work to be done, either on tiie system, or by the system on its surroundings. The relationship between chemical change and electrical work is important, and we will consider it in some detail in Chapter 20, "Electrochemistry." Most commonly, fliough, die only kind of work produced by chemical change is mechanical work. We usually carry out reactions in the laboratory at constant (atmospheric) pressure. Under these circumstances mechanical work wcurs when a gas is produced or consumed in die reaction. Consider, for example, die reaction of zinc metal witii hydrochloric acid solution ... 

Method 2. Place a 3 0 g. sample of the mixture of amines in a flask, add 6g. (4-5 ml.) of benzenesulphonyl chloride (or 6 g. of p-toluenesulphonyl chloride) and 100 ml. of a 5 per cent, solution of sodium hydroxide. Stopper the flask and shake vigorously until the odour of the acid chloride has disappeared open the flask occasionally to release the pressure developed by the heat of the reaction. AUow the mixture to cool, and dissolve any insoluble material in 60-75 ml. of ether. If a solid insoluble in both the aqueous and ether layer appears at this point (it is probably the sparingly soluble salt of a primary amine, e.g., a long chain compound of the type CjH5(CH2) NHj), add 25 ml. of water and shake if it does not dissolve, filter it off. Separate the ether and aqueous layers. The ether layer will contain the unchanged tertiary amine and the sulphonamide of the secondary amine. Acidify the alkaline aqueous layer with dilute hydrochloric acid, filter off the sulphonamide of the primary amine, and recrystaUise it from dilute alcohol. Extract the ether layer with sufficient 5 per cent, hydrochloric acid to remove all the tertiary amine present. Evaporate the ether to obtain the sulphonamide of the secondary amine recrystaUise it from alcohol or dilute alcohol. FinaUy, render the hydrochloric acid extract alkaline by the addition of dilute sodium hydroxide solution, and isolate the tertiary amine. 

Of course, there are a couple advantages to using HCI as the hy-drolyzer. Since using hydrochloric acid means that all that fat MDA or amphetamine is in the water solution, the chemist can vacuum filter the solution to get rid of all the tar and crap which will give a remarkably clean water solution. The X is released by basifying and extracting with solvent. 

To produce a moulding composition, aniline is first treated with hydrochloric acid to produce water-soluble aniline hydrochloride. The aniline hydrochloride solution is then run into a large wooden vat and formaldehyde solution is run in at a slow but uniform rate, the whole mix being subject to continuous agitation. Reaction occurs immediately to give a deep orange-red product. The resin is still a water-soluble material and so it is fed into a 10% caustic soda solution to react with the hydrochloride, thus releasing the resin as a creamy yellow slurry. The slurry is washed with a counter-current of fresh water, dried and ball-milled. 

Heretofore, no economical method for preparing pure phytic acid was known. The classical method was to dissolve calcium phytate in an acid such as hydrochloric acid, and then add a solution of a copper salt, such as copper sulfate to precipitate copper phytate. The latter was suspended in water and treated with hydrogen sulfide, which formed insoluble copper sulfide and released phytic acid to the solution. After removing the copper sulfide by filtration, the filtrate was concentrated to yield phytic acid as a syrup. 

Note. If certain sulphides are treated with hydrochloric acid, hydrogen sulphide is evolved and can be absorbed in an ammoniacal cadmium chloride solution upon acidification hydrogen sulphide is released. 

A similar study was conducted by Dimitrijevi6 et al. with neutral solutions of a-Fe203. The yield of Fe was found to be very low. However, a large Fe yield was found after dissolution of the colloid by hydrochloric acid under an argon atmosphere. This showed that electrons donated by the free radicals penetrated deep into the colloidal particles to reduce iron to F, . Buxton et al. observol in a study on the reductive dissolution of colloidal Fe304 that Fe ions in this material are less readily released into the aqueous phase than reduced Fe ions. 

Ecologically, accidental releases of solution forms of hydrochloric acid may adversely affect aquatic life by including a transient lowering of the pH (i.e., increasing the acidity) of surface waters. Releases of hydrochloric acid to surface waters and soils will be neutralized to an extent due to the buffering capacities of both systems. The extent of these reactions will depend on the characteristics of the specific environment. 

Typically, acid soils are titrated with a sodium or calcium hydroxide [NaOH or Ca(OH)2] solution and basic soils with hydrochloric acid (HC1), and pH changes are most commonly followed using a pH meter. Carbonates in basic soils release C02 during treatment with HC1, thus making the titration more difficult. For this reason, carbonates are often determined by other methods. It is important to keep in mind that basic solutions react with carbon dioxide in air and form insoluble carbonates. This means that either the basic titrant is standardized each day before use or the solution is protected from exposure to carbon dioxide in air. Specific descriptions of titrant preparation, primary standards, and the use of indicators and pH meters in titrations can be found in Harris [1] and in Skoog et al. [2],... 

Davison and Lishman [105] described a method in which sulphide is released from the sediment using 5.93mol L 1 hydrochloric acid, and the resulting solution is separated from the sediment by filtration in a sealed system of syringes. The concentrated sulphide is determined spectrophotometrically at 670nm as ethylene blue. The limit of detection is 2mg kg-1 expressed as mass of sulphide in dry mass of sediment. The relative standard deviation was 5% for a sediment containing 118mg kg 1 sulphide. 

---