Hydrochloric acid molarity

Fig. 41. Elution peak position of the tetrapositive ions vs hydrochloric acid molarity. ... 

Commercially available concentrated hydrochloric acid is 37.0% w/w HCl. Its density is 1.18 g/mL. Using this information calculate (a) the molarity of concentrated HCl, and (b) the mass and volume (in milliliters) of solution containing 0.315 mol of HCl. 

Zirconium hydroxy oxychloride [18428-88-17, nominally ZrO(OH)Cl, is produced by dissolving hydrous zirconia in hydrochloric acid in an equal molar proportion, and is available only in solution. Other oxychlorides with Cl Zr ratios <2 are discussed in Reference 199. 

Chloride Reductant. Processes prior to 1945 used hydrochloric acid as both the acid and reducing agent. Hydrochloric acid is oxidized to chlorine gas and chlorate is reduced to chlorine dioxide. The overall stoichiometry produces a 2 1 molar ratio of chlorine dioxide to chlorine. Sodium chloride is a by-product ... 

The preparation of cyclohexylmagnesium bromide is described on p. 22. The solution may be standardized by titrating against 0.5 N hydrochloric acid, and exactly one mole equivalent is used in the preparation. Five cubic centimeters of cyclohexylmagnesium bromide solution is slowly added to 20 cc. of water, an excess of the standard acid is added, and the excess acid titrated with sodium hydroxide. If 85 g. (3.5 moles) of magnesium, one liter of dry ether, and 571 g. of cyclohexyl bromide (3.5 moles) are used, a solution results which is about 2 molar. 

In an altogether different type of approach, the hydrazone is formed in situ as a lithium salt. Wilson et al. (80JHC389) described this approach in the one-pot synthesis of 5-aryl-2-phenylpyrazol-3-ones 72a-f from the corresponding hydrazones 65a-f (Scheme 20). The latter were obtained by condensing ketones 64a-f with phenylhydrazine. Treatment of hydrazones 65a-f with n-butyllithium in dry THF, followed by the addition of half a molar equivalent of diethyl carbonate 67 and then quenching the reaction mixture with hydrochloric acid, produced pyrazol-3-ones 72a-f, along with products 71. The yields of the products 72 are in the range 22-97%. Four intermediates—66a-f, 68a-f, 69a-f, and 70a-f— were proposed for this reaction. 

This is a crystalline product of insulin and an alkaline protein where the protein/insulin ratio is called the isophane ratio. This product gives a delayed and uniform insulin action with a reduction in the number of insulin doses necessary per day. Such a preparation may be made as follows 1.6 g of zinc-insulin crystals containing 0.4% of zinc are dissolved in 400 ml of water, with the aid of 25 ml of 0.1 N hydrochloric acid. To this are added aqueous solutions of 3 ml of tricresol, 7.6 g of sodium chloride, and sufficient sodium phosphate buffer that the final concentration is As molar and the pH is 6.9. 

A solution of 100 g (1.7 mols) of isopropylamine in 60 cc of water was stirred into a solution of 4-hydroxyphenoxypropylene oxide. After the exothermic reaction has subsided, the reaction mixture was heated for two hours at 60Thereafter, the aqueous ethanol was distilled off, and the solid residue was dissolved in aqueous hydrochloric acid comprising more than the theoretical stoichiometric molar equivalent of hydrochloric acid. The aqueous acid solution was extracted with ether and was then made alkaline with sodium hydroxide, whereby a solid crystalline precipitate was formed which was filtered off and dried over phosphorus pentoxide. The product was 1,1 -(4 -hvdroxvphenoxv)-2-hvdroxv-3-isopropylamino-pro-pane. Its hydrochloride had a melting point of 166°Cto 169°C. 

It is frequently necessary to convert from one concentration unit to another This problem arises, for example, in making up solutions of hydrochloric acid. Typically, the analysis or assay that appears on the label (Figure 10.2, p. 263) does not give the molarity or molality of the add. Instead, it lists the mass percent of solute and the density of the solution. 

The label on a bottle of concentrated hydrochloric acid. The label gives the mass percent of HCI in the solution (known as the assay] and the density (or specific gravity) of the solution. The molality, molarity, and mole fraction of HCI in the solution can be calculated from this information. 

If the solution contains carbonate (Procedure A), methyl orange, methyl orange-ihdigo carmine, or bromophenol blue must be used in standardisation against hydrochloric acid of known molar concentration. Phenolphthalein or indicators with a similar pH range, which are affected by carbon dioxide, cannot... 

G.10 (a) A sample of 1.345 m I<2S04(aq) of volume 12.56 mL is diluted to 250.0 mL. What is the molar concentration of K2S04 in the diluted solution (b) A sample of 0.366 m HCl(aq) of volume 25.00 mL is drawn from a reagent bottle with a pipet. The sample is transferred to a flask of volume 125.00 mL and diluted to the mark with water. What is the molar concentration of the dilute hydrochloric acid solution ... 

Self-Test L.3A A student used a sample of hydrochloric acid that was known to contain 0.72 g of hydrogen chloride in 500.0 mL of solution to titrate 25.0 ml. of a solution of calcium hydroxide. The stoichiometric point was reached when 15.1 mL of acid had been added. What was the molarity of the calcium hydroxide solution ... 

Hydrochloric acid oxidizes zinc metal in a reaction that produces hydrogen gas and chloride ions. A piece of zinc metal of mass 8.5 g is dropped into an apparatus containing 800.0 mL of 0.500 M HCl(aq). If the initial temperature of the hydrochloric acid solution is 25°C, what is the final temperature of this solution Assume that the density and molar heat capacity of the hydrochloric acid solution are the same as those of water and that all the heat is used to raise the temperature of the solution. 

C04-0034. While cleaning a laboratory, a technician discovers a large bottle containing a colorless solution. The bottle is labeled Ba (OH)2, but the molarity of the solution is not given. Concerned because of the toxicity of Ba ions, the technician titrates with a solution of hydrochloric acid standardized at 0.1374 M. A 25.00-mL sample of the barium hydroxide solution requires 36.72 mL of the HCl solution to reach the stoichiometric point. What is the concentration of Ba in the solution ... 

C18-0130. The titration of 25.0 mL of a mixture of hydrochloric acid and formic acid with 0.578 M NaOH gave the titration curve below. What are the molarities of HCl and HCO2 H in the solution ... 

Despite the previous comments there are dangerous forms of this metal. Thus, the Ru-Zn alloy, when treated by hydrochloric acid leads to zinc dissolving into a very porous ruthenium, which detonates in air spontaneousiy. The same goes for ruthenium, which is obtained by reduction of its salts by sodium borohydride. It is recommended to reduce ruthenium salts using hydrazine, which is reputed to be not dangerous . However, with ruthenium trichioride this reaction seems to be not dangerous only when hydrazine has a very low molar ratio (0.9 mol per cent). If it is not the case, a huge volume of gas could constitute an important pressure risk. 

Ferrous chloride-hydrochloric acid mixtures catalyzed the thermal decomposition of sulphonyl azides in isopropyl alcohol to give occasionally almost quantitative yields of sulphonamide and acetone, and the molar ratio of azide consumed to ferric chloride formed was typically of the order of 20 to 1 21>. 

Table 7 Values of X and —Ho, and of log Ch and login molarity units, for aqueous hydrochloric acid at 25°C at different values of wt% acid.

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