Acid Hydrochloric Perchloric

The metal has a silvery appearance and takes on a yellow tarnish when slightly oxidized. It is chemically reactive. A relatively large piece of plutonium is warm to the touch because of the energy given off in alpha decay. Larger pieces will produce enough heat to boil water. The metal readily dissolves in concentrated hydrochloric acid, hydroiodic acid, or perchloric acid. The metal exhibits six allotropic modifications having various crystalline structures. The densities of these vary from 16.00 to 19.86 g/cms. 

Perchloric acid Sulfuric acid Hydrochloric acid Nitric acid... 

Steroidal cis vicinal diols at the 1,2-, ° 2,3-, ° 5,6- or 11,12- " positions can be selectively protected as acetonides, prepared by reaction with acetone at room temperature or at higher temperatures in the presence of hydrochloric, perchloric or -toluenesulfonic acids. Cis nonvicinal-diols can be similarly protected. 

The decomposition of the carbonate may be effected with dilute hydrochloric acid, dilute perchloric acid, or phosphoric(V) acid. The last-named acid is perhaps the most convenient because of its comparative non-volatility and the fact that the reaction can be more easily controlled than with the other acids. If dilute hydrochloric acid is employed, a short, water-cooled condenser should be inserted between the decomposition flask and the absorption train (see below). 

Best results are obtained when the reaction is carried out under acidic conditions. The products are isolated in the form of their stable salts 3 with hydrochloric, perchloric or sulfuric acid.256-257 a-Hydroxymethylene ketones do not condense with benzene-1,2-diamine to give benzodiazepines if the carbonyl group is adjacent to an aromatic ring.258... 

It is important to emphasize that often — but not always — the performance of a product with a chemical depends heavily on the manufacturer and a specific product model. A model that performs well with one chemical may perform poorly with another chemical, even when the chemicals are in the same chemical class. This is illustrated by the Edmont Model 37-165 glove which was tested against all five acids. This glove shows good protective properties with hydrochloric, perchloric, and phosphoric acids, but exhibits degradation in nitric and sulfuric acids. 

See Chromic acid, also Hydrochloric acid, also Perchloric acid, all above... 

Wiersma and Lee [164] determined selenium in lake sediments. The sample is digested with 4 1 concentrated nitric acid 6% perchloric acid and the residue treated with 6M hydrochloric acid then reduced with H PO. The fluorescing agent used was 2,3 diaminonaphthalene. 3 2... 

In this method approximately 19 samples of marine sediment were oven dried at 110°C then digested with nitric acid-perchloric acid and hydrofluoric acid-hydrochloric acid. The digested solution is made up to 50ml of an equal volume mixture of 6M hydrochloric acid and 2M nitric acid. 0.1ml or less of the digest was pipetted into the hydride generator, followed by 1ml 2M acetic acid, diluted to 100ml with double distilled water and reacted with sodium borohydride. 

Chloric acid, HC103 Hydrobromic acid, HBr Hydrochloric acid, HC1 Hydroiodic acid, HI Nitric acid, HN03 Perchloric acid, HCIO4 Sulfuric acid, H2S04... 

Wet chemical decomposition in a closed system, with nitric acid or mixed acids consisting of nitric acid, hydrochloric acid, perchloric acid, hydrogen peroxide and hydrofluoric acid. The following devices are available ... 

Strong acid/strong base titrations are used in pharmacopoeial assays of perchloric acid, hydrochloric acid, sulphuric acid and thiamine hydrochloride. 

Determination of Mg in the hard tissues (shell and pearl) of shellfish by the ICP-AES method involves dissolution of the sample by hot concentrated nitric acid, hydrochloric acid and perchloric acid. However, the large excess of Ca in the matrix strongly interferes with the end analysis and causes damage to the torch. After adjusting the pH to 4.5, the Mg ions were extracted by a 0.01 M solution of 3-methyl-l-phenyl-4-trifluoroacetylpyrazol-5-one (16) in dibutyl ether and the ICP-AES analysis was carried out by direct injection of the organic solution. ... 

Strong and weak acids are classified by how completely they ionize in solution. For example, HC1 is classified as a strong acid because it is completely ionized to H+ and Cl ions. Acetic acid is classified as a weak acid because it does not totally ionize in solution. As mentioned earlier, weak acids such as acetic acid have higher pKas. The pKa for acetic acid is 4.75. The negative antilog of this value (1.76 x 10 5) can be used to calculate the concentrations at equilibrium of the acetate and hydrogen ions. Strong acids include perchloric, hydrochloric, sulfuric, nitric, and hydriodic... 

In aqueous acetic acid, the disproportionation of the platinum still occurs quite rapidly, and it can be suppressed further by adding mineral acid. Hydrochloric acid is often used, but this has a disadvantage in that the exchange rate is inversely proportional to the chloride ion concentration. Perchloric acid has been found to be more satisfactory (55). The platinum(II) catalyst most used is sodium or potassium tetrachloropla-tinate(II). An aromatic compound added to the reaction mixture also inhibits disproportionation of the platinum(II) complex—benzene, pyrene, and other aromatics have been used. A comparative study of the effect of various aromatics on the H—D exchange in alkanes has been carried out (55). Even under optimum conditions, the disproportionation [Eq. (4)] still takes place, and the catalytic platinum(II) is slowly removed from the reaction mixture. To get useful rates of exchange in alkanes, temperatures of 100° to 120°C have to be used, and the disproportionation rate increases with temperature. 

Oxidising adds such as nitric, chloric and iodic acids induce rapid decomposition of trithionic acid with formation of sulphur and sulphuric acid 2 the presence of other acids, for example hydrochloric, perchloric or dilute sulphuric acid, also hydrogen sulphide, is without any harmful effect.3 Addition of sulphurous acid causes the gradual formation of a mixture of all the polythionic acids. 

The acid catalysis of the hydrolysis of acetic anhydride was later investigated by Gold and Hilton292 using aqueous solutions of hydrochloric, perchloric, sulphuric and phosphoric acids at 0°C. The first-order rate coefficient for hydrolysis is approximately proportional to h0 for all of these acids over a wide range of concentrations and this correlation is far better than with log [H+ ]. The mechanism proposed by these authors is... 

Sodium hydrosulphite reduces arsenates and arsenites, yielding precipitates containing sulphides the composition of which varies with conditions. In strongly acid solutions arsenic trisulphide is the main product.2 Sodium thiosulphate also precipitates arsenic as the trisulphide from acid solutions,3 but the amount of precipitation depends on the nature and concentration of the acid present. Thus, with hydrochloric, perchloric or sulphuric acid, the precipitation reaches a maximum of 50 to 80 per cent, for 0-1N acid,4 and above this concentration the amount of precipitation falls to zero with hydrochloric acid but passes through a minimum with perchloric acid at N concentration and with sulphuric acid at 2 to 3N concentration. At still higher acid concentrations precipitation becomes almost quantitative. 

Generally epoxide hydrations cited here will be of two types. The first involves heating the epoxide with water alone at 100-125°. frequently in a sealed tube The second, treating it with water at moderate temperaturew in the presence of a trace of acid. Meet commonly employed for this purpose is sulfuric acid although perchloric acid has likewise keen reported oil occasion Acetic acid, formic acid, hydrochloric add, hydrobromjc acid, and hydroiodio arid can be used... 

Compared with mineral acids such as hydrochloric, perchloric, nitric, and sulfuric acids, the carboxylic acids, CH3(CH2) C02H, are weak. The extent of... 

The effects of soil sample preparation procedures for the determination of chromium in soils have been reported [38]. The optimum conditions included the use of an homogeneous sample with a mass of less than 4 kg, a grain diameter of less than 0.25 mm, digestion with a solution of nitric acid plus perchloric acid (3 2) and hydrochloric acid after dry ashing, with the addition of 1% lanthanum or 1% ammonium chloride to eliminate interferences. 

Several acids and acid mixtures have been used for the digestion of soil samples prior to the analysis of lead, including nitric acid-perchloric acid (1 + 1) [105], hydrochloric acid [106], perchloric acid [107], nitric acid-hydrofluoric acid (1 + 1) [ 108,109] and aqua regia [52],... 

---