Hydrochloric acid stock solution

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). 

Folic Acid Stock Solutions Accurately weigh, in a closed system, 50 to 60 mg of USP Folic Acid Reference Standard that has been dried to constant weight and stored in the dark over phosphorus pentoxide in a desiccator. Dissolve in approximately 30 mL of 0.01 N sodium hydroxide, add approximately 300 mL of water, adjust to pH 7.5 with 1 2 hydrochloric acid, and dilute with additional water to a final folic acid concentration of exactly 100 p,g/mL. Store under toluene in the dark at 10°. 

Prepare the final Folic Acid Stock Solution by taking 100 mL of the intermediate Folic Acid Stock Solution, adding approximately 500 mL of water, adjusting to pH 7.5 with dilute hydrochloric acid or sodiumhydroxide as necessary, and diluting with additional water to a final volume of 1 L. Store under toluene in the dark at 10°. This final Folic Acid Stock Solution has a concentration of 100 ng/mL. 

Prepare a trypsin stock solution by dissolving 20 mg of the enzyme in 1 mM hydrochloric acid aqueous solution to a 1-mg/ml final concentration. 

Rinse your buret with several 1-mL portions of an approximately 0.1 M hydrochloric acid, HCl, solution provided on the reagent bench. Then titrate sample 1 until the color of the solution matches that of your prepared stock solution of 0.1 M H3BO3-O.05 M NaCl. Record in TABLE 35.2 the molarity and the volume of HCl solution that you have used. 

Hydrochloric acid-hydriodic acid elutriant. Prepared by mixing 1 ml of hydriodic acid stock solution with 9 ml of concentrated hydrochloric acid. The precipitate formed by hydrazine is removed by centrifuging the supernatant then is saturated with gaseous hydrogen chloride. The reagent must be prepared every few days because it decomposes easily. 

Stock Solution 1 2.18 g of recrystallized insulin are dissolved in 25 ml of 0.1 N hydrochloric acid, and distilled water to a volume of 125 ml is added. 

To restore old stocks of corroded glass, treatment in hot 1% sodium hydroxide solution followed by rinsing in 5<> o hydrochloric acid and a final rinse in pure water at room temperature is recommended. ... 

Prepare a calcium stock solution (1000 mg L "1) by dissolving 2.497 g of dried calcium carbonate in a minimum volume of 1M hydrochloric acid about 50 mL will be required. When dissolution is complete, transfer the solution to a 1 L graduated flask and make up to the mark with de-ionised water. An intermediate calcium stock solution is prepared by pipetting 50 cm of the stock solution into a 1 L flask and making up to the mark with de-ionised water. 

Prepare a blank solution by carrying through all the sequences of the separation procedures using a hydrochloric acid solution to which no alloy has been added, and then measure the absorption given by this blank solution, by a series of standard solutions containing from 1 to 10 /rg Pb mL 1 prepared by suitable dilution of the lead caprate stock solution (see Note), and finally of the extract prepared from the sample of alloy. Plot the calibration curve and determine the lead content of the alloy. 

Alternatively make up a stock solution of 10 g 4-(dimethylamino)-benzaldehyde in concentrated hydrochloric acid and dilute one part by volume with 4 to 10 parts by volume acetone inunediately before spraying [20. 25, 26, 28, 29, 44],... 

Stannous chloride stock solution. Dissolve 40 g of stannous chloride in 100 mL of concentrated hydrochloric acid (37%)... 

A fluoride electrode is utilized to determine the amount of fluoride ion in tap water. The water also contains chloride, with the selectivity ratio F CI" being 3000 1. An aqueous stock solution is known to contain 10" mol dm of NaF (when acidified to pH 5.5 with hydrochloric acid), and gave an emf of 0.880 V. What is the concentration of NaF (in the same acid) if the emf changes to 0.804 V ... 

Magnesium stock solution, 1000 pg Mg + mb - dissolve 1.6581 g magnesium oxide (previously dried at 105°C overnight and cooled in a desiccator) in the minimum of hydrochloric acid (approximately 5 M). Dilute with water to 1 I in a volumetric flask to obtain a solution of 1000 pg Mg2+ mM. 

Potassium stock solution, 1000 pg K+ mh - weigh 1.293 g potassium nitrate (previously dried for 1 h at 105°C and cooled in a desiccator) into a 100-ml beaker. Dissolve in water, add 1 ml hydrochloric acid (approximately 36% m/m HCI) and 1 drop of toluene, then transfer with washings to a 500-ml volumetric flask, make up to the mark and mix well by shaking. 

Alternatively, the bomb combustion dissolution procedure can be combined with the hydride evolution method previously described for arsenic, tin, and bismuth. After completion of the bomb combustion and absorption of gases into the 10 ml of water, the solids are filtered out and the filtrate collected into a 50 ml volumetric flask containg 20 ml of hydrochloric acid. This is a suitable stock solution for the hydride evolution method. 

Method 2. The steroid residue is dissolved in methanol and then acidified by 3-4 drops of concentrated hydrochloric acid. 2,4-Dinitrophenylhydrazine is dissolved in methanol as a stock solution (0.2%). This is added to the residue in a slight molar excess, taking into account the number of carbonyl groups contained in the steroid. The mixture is then stirred and warmed for 5 min at 50 °C. An aliquot portion of this solution may be used for chromatography. If methanol is not suitable as a solvent for HPLC, then the reaction mixture may be evaporated and dissolved in an appropriate solvent such as chloroform or ethyl acetate. 

Keep stock of all azides very low. Stamp date and receipt on package. Wear butyl rubber gloves, eye protection, and laboratory coat. In the fume hood and behind a safety shield, add the azide to 6 M hydrochloric acid (cautiously add a volume of concentrated acid to an equal volume of cold water 150 mL for each 1 g of azide). While stirring, add granular tin (10 g for each 1 g of azide). Continue stirring at room temperature for 30 minutes. Decant or filter the solution into a pail of cold water. Neutralize with sodium carbonate and pour into the drain with at least 50 times its volume of water. Reuse the excess tin or discard as normal refuse.2... 

Bichromate stock solution, 100.0ml Hydrochloric acid, concentrate, 2.4ml Distilled water to make 1.0 liter... 

Standard Solutions Transfer 190.7 mg of potassium chloride, previously dried at 105° for 2 h, into a 1000-mL volumetric flask, dilute to volume with water, and mix. Transfer 100.0 mL of this solution to a second 1000-mL volumetric flask, dilute to volume with water, and mix to obtain a Stock Solution containing 10 jxg of potassium per milliliter (equivalent to 19.07 (xg of potassium chloride). Pipet 10.0-, 15.0-, and 20.0-mL aliquots of the Stock Solution into separate 100-mL volumetric flasks add 2.0 mL of a 1 5 solution of sodium chloride and 1.0 mL of hydrochloric acid to each dilute with water to volume and mix. The Standard Solutions obtained contain, respectively, 1.0, 1.5, and 2.0 (ig of potassium per milliliter. 

Cadmium Calibration Standards Tare three clean, dry 4-oz polyethylene bottles (or equivalent). Add approximately 50 g of High-Purity Water to each. Slowly add 28 1 g of concentrated nitric acid, mix thoroughly, slowly add 12 1 g of concentrated hydrochloric acid, and mix thoroughly again. Using a precision micropipet, add 10, 50, and 500 pL, respectively, of Cadmium Stock Solution to one of each of the bottles. Dilute each solution to 100.0 0.1 g with High-Purity Water, and mix thoroughly to obtain calibration standards with 0.1, 0.5, and 5.0 mg/kg, respectively. 

Stock Lanthanum Solution Transfer 5.86 g of lanthanum oxide (La203) into a 100-mL volumetric flask, wet with a few milliliters of water, slowly add 25 mL of hydrochloric acid, and swirl until the lanthanum oxide is completely dissolved. Dilute to volume with water, and mix. 

Stock Calcium Solution Transfer 124.8 mg of calcium carbonate (CaC03) previously dried at 200° for 4 h, into a 100-mL volumetric flask, carefully dissolve in 2 mL of 2.7 A hydrochloric acid, dilute to volume with water, and mix. This 500-mg/kg calcium solution is commercially available. 

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