Hydrochloric acid standard solution

For the preparation of standard cobalt solutions, use analytical grade cobalt(II) chloride or spectroscopically pure cobalt dissolved in hydrochloric acid subject solutions containing 0, 5, 10, 25, 50, 100, 150, and 200 jug of Co to the whole procedure. 

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 ... 

An ultraviolet spectrophotometric analysis is used to determine content uniformity of triprolidine hydrochloride in tablet formulations.1 The triprolidine hydrochloride is extracted from finely powdered tablets with dilute hydrochloric acid. The solution is filtered and diluted to a concentration of approximately 10 Jg triprolidine hydrochloride per ml. The absorbance at 290 nm of the extracted triprolidine hydrochloride solution in 1 cm cells is compared against NF Triprolidine Hydrochloride Reference Standard prepared in dilute hydrochloric acid at the 10 pg/ml level. 

There is also a standard test method for determination of major and minor elements in coal ash by inductively coupled plasma (ICP)-atomic emission spectrometry (ASTM D-6349). In the test method, the sample to be analyzed is ashed under standard conditions and ignited to constant weight. The ash is fused with a fluxing agent followed by dissolution of the melt in dilute acid solution. Alternatively, the ash is digested in a mixture of hydrofluoric, nitric, and hydrochloric acids. The solution is analyzed by (ICP)-atomic emission spectrometry for the elements. The basis of the method is the measurement of atomic emissions. Aqueous solutions of the samples are nebulized, and a portion of the aerosol that is produced is transported to the plasma torch, where excitation and emission occurs. Characteristic line emission spectra are produced by a radio-frequency inductively coupled plasma. A grating monochromator system is used to separate the emission lines, and the intensities of the lines are monitored by photomultiplier tube or photodiode array detection. The photocurrents from the detector... 

For analysis of acids, esters, alcohols, ketones, aldehydes and fiirfiual the test solution was prepared by dilution of a weighed sam de of clear ftaction of the condensate 10 g to 100 ml with distillate water. The content of acids and esters was determined by potentiometric titration, using potassium hydroxide and hydrochloric acid standard volumetric solutions. c(KOH) = 0.1 mol/l c(HCl) = 0.1 molfi. An automatic potentiometric titration assembly RTS - 822 Radiometer (Denmark) was used. 

Standard Acid Solutions Standard acid solutions in the range 8 x 10 -1 X 10 M are made by appropriate dilutions of a 0.1 M hydrochloric acid stock solution (e.g., Titrisol). 

The analysis of the copper-ammine complex for the ammonia, NH3, content will involve an acid-base "back titration." In this analysis, you will react the complex with an accurately measured volume of standardized hydrochloric acid, HCl, solution. The volume of HCl solution should be sufficient to react with all the ammonia and leave some excess HCl. The excess HCl will then be back reacted with standardized sodium hydroxide, NaOH, solution. The difference between the number of moles of HCl added and the number of moles of excess HCl will give the number of moles of ammonia in your measured quantity of copper-ammine complex. For your information, you cannot titrate the ammonia directly with HCl because of problems with seeing the color changes of the appropriate indicator in the presence of the colored copper-ammine complex. 

Dimethylthtazolidine-4-carboxylic acid standard solution (Vp). Add 500 pi of concentrated hydrochloric acid to 100 mg of L-5,5-dimethylthiazolidine-4-carlx)xylic acid and make up to 100 ml with isopropanol. Add 500 pi of concentrated hydrochloric acid to 5fX) pi, IWX) pi, 1500 pi, etc., of... 

Dissolve 7.5 g of trishydroxymethylaminomethane in 3000 ml of distilled water. Adjust the pH to between 7.7 and 7.8 by the dropwise addition of 20% hydrochloric acid. This solution should be dispensed into clean 250-ml Erlenmeyer flasks to the extent of about 150 ml per flask, the flasks stoppered with suitable loose fitting caps (cotton wool in cheesecloth, stainless steel caps, etc.) and autoclaved at 15 psi for 15 min. Use the contents of each flask for one batch of samples and standards and then discard them. 

The anhydrous chloride is prepared by standard methods. It is readily soluble in water to give a blue-green solution from which the blue hydrated salt CuClj. 2H2O can be crystallised here, two water molecules replace two of the planar chlorine ligands in the structure given above. Addition of dilute hydrochloric acid to copper(II) hydroxide or carbonate also gives a blue-green solution of the chloride CuClj but addition of concentrated hydrochloric acid (or any source of chloride ion) produces a yellow solution due to formation of chloro-copper(ll) complexes (see below). 

Tin ores and concentrates can be brought into solution by fusing at red heat in a nickel cmcible with sodium carbonate and sodium peroxide, leaching in water, acidifying with hydrochloric acid, and digesting with nickel sheet. The solution is cooled in carbon dioxide, and titrated with a standard potassium iodate—iodide solution using starch as an indicator. 

The assay method involves the reaction of benzaldehyde with hydroxylamine hydrochloride in an alcohoHc solution. Benzaldehyde oxime, water, and hydrochloric acid are the products of the reaction. The hydrochloric acid formed is then titrated with standard caustic solution to determine the benzaldehyde assay. 

The sodium carbonate content may be deterrnined on the same sample after a slight excess of silver nitrate has been added. An excess of barium chloride solution is added and, after the barium carbonate has setded, it is filtered, washed, and decomposed by boiling with an excess of standard hydrochloric acid. The excess of acid is then titrated with standard sodium hydroxide solution, using methyl red as indicator, and the sodium carbonate content is calculated. 

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. 

One 1-ml aliquot is added to 1.0 ml of freshly-distilled 1,2-dibromo-ethane (bp 132°C) in an oven-dried flask which contains a static atmosphere of nitrogen or argon. After the resulting solution has been allowed to stand at 25°C for 5 min, it Is diluted with 10 rat of water and titrated for base content (residual base) to a phenolphthalein endpoint with standard 0.100 M hydrochloric acid. The second 1-mL aliquot is added cautiously to 10 ml of water and then titrated for base content (total base) to a phenol phthalein endpoint with standard aqueous 0.100 M hydrochloric acid. The methyllithium concentration is the difference between the total base and residual base concentrations.2 Alternatively, the methynithiura concentration may be determined by titration with a standard solution of sec-butyl alcohol employing 2,2 -bipyridyl as an indicator. 

The pH of the mixture was adjusted to 7.5 by adding a saturated sodium bicarbonate solution. After being washed twice with diethyl ether, the reaction solution was acidified to pH 2 with dilute hydrochloric acid and extracted with ether. The ether solution containing the free penicillin was washed twice with water and then extracted with 50 ml of N potassium bicarbonate solution. After freeze drying of the obtained neutral solution, the potassium salt of o-azidobenzylpenicillin was obtained as a slightly colored powder (11.2 grams, 54% yield) with a purity of 55% as determined by the hydroxylamine method (the potassium salt of penicillin G being used as a standard). 

Sufficient dry ether (approximately 100 ml.) is added to bring the organomagnesium products into solution. Aliquot portions of the solution are then added to a known volume of standard hydrochloric acid, and the excess acid is determined by titration with standard base. Yields determined in this way tend to be a few percent higher than those determined by collection of w-butane (Note 12). 

A solution of dry ammonia gas in absolute ethyl alcohol is prepared and titrated against standard hydrochloric acid, using methyl orange as the indicator. The solution should contain at least 9 per cent of ammonia by weight (Note 5). 

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