Sodium hydroxide free from carbonate

Let this volume correspond to V mL 1M HC1. To another sample, a measured excess of standard 0.1M sodium hydroxide (free from carbonate) over that required to transform the hydrogencarbonate to carbonate is added ... 

For the purpose of this experiment, sodium hydroxide free from carbonate is required. This is best prepared as follows Metallic sodium in roughly weighed amount, according to the quantity and strength of the solution required, is freed from the adhering paraffin or other liquid, and from the crust of oxide, and placed in the funnel F (Fig. 64), made of nickel... 

Prepare approximately fourth-normal solutions of hydrochloric acid and of sodium hydroxide, free from carbonate (see p. 197), and determine their strength by titration. 

Orthophosphoric Acid may be titrated with sodium or potassium hydroxide free from carbonate. The equivalent point indicating NaH2P04 occurs at pH = ca. 4-2, which is within the transition range of methyl yellow, methyl orange and bromophenol blue. The endpoint tint should be matched against that of a comparison solution containing about the same concentration of NaH2P04. 

Twenty cc of commereial formaldehyde is measured into ao equal volume of distilled water, to which is added two drops of bromothymol blue solution, prepared by dissolving 0,10 g bromothymol blue in 101 cc per cent aliiohol. The formaldehyde solution IS then titrated with normal or O.l.V sodium hydroxide (free of carbonate). One cc of normal alkali is equivalent to 0-04602 g formic acid. The acid content is calculated as per cent formic acid by weight, the weight of sample being determined from the approximate density of the formaldehyde analyzed. 

Chill the concentrated solution of the amine hydrochloride in ice-water, and then cautiously with stirring add an excess of 20% aqueous sodium hydroxide solution to liberate the amine. Pour the mixture into a separating-funnel, and rinse out the flask or basin with ether into the funnel. Extract the mixture twice with ether (2 X25 ml.). Dry the united ether extracts over flake or powdered sodium hydroxide, preferably overnight. Distil the dry filtered extract from an apparatus similar to that used for the oxime when the ether has been removed, distil the amine slowly under water-pump pressure, using a capillary tube having a soda-lime guard - tube to ensure that only dry air free from carbon dioxide passes through the liquid. Collect the amine, b.p. 59-61°/12 mm. at atmospheric pressure it has b.p. 163-164°. Yield, 18 g. 

Strongly basic anion exchangers (polystyrene quaternary ammonium resins). These resins (Duolite A113, Amberlite 400, etc.) are usually supplied in the chloride form. For conversion into the hydroxide form, treatment with 1M sodium hydroxide is employed, the volume used depending upon the extent of conversion desired two bed volumes are satisfactory for most purposes. The rinsing of the resin free from alkali should be done with de-ionised water free from carbon dioxide to avoid converting the resin into the carbonate form about 2 litres of such water will suffice for 100 g of resin. An increase in volume of about 20 per cent occurs in the conversion of the resin from the chloride to the hydroxide form. 

A mixture of 6.008 g of citric acid, 3.893 g of potassium dihydrogenphosphate, 1.769 g of boric acid, and 5.266 g of pure diethylbarbituric acid is dissolved in water and made up to 1 L. The pH values at 18°C of mixtures of 100 mL of this solution with various volumes (20 of 0.2M sodium hydroxide solution (free from carbonate) are tabulated below. 

Sodium hydroxide stock solutions were prepared of three different concentrations, viz., 0.1, 1.0 and 10M. The 0.1 and 1.0M solutions were obtained by diluting Baker reagent grade Dilut-it standardized solutions. The 10M solution was prepared by dilution of 50% Baker Analyzed sodium hydroxide (18.86M). Carbonate free water was used for all dilutions and the solutions were protected from contact with air. 

Heat over a free flame or an electric heater until the solution has attained a clear blue color and the walls of the flask are free from carbonized material. Cautiously add 20 mL of water, cool, then add through a funnel 30 mL of a 2 5 solution of sodium hydroxide, and rinse the funnel with 10 mL of water. Connect the flask to a steam distillation apparatus, and immediately begin the distillation with steam. Collect the distillate in 15 mL of a 1 25 solution of boric acid to which has been added 3 drops of methyl red-methylene blue TS and enough water to cover the end of the condensing tube. Continue passing the steam until 80 to 100 mL of distillate has been collected, then remove the absorption flask, rinse the end of the condenser tube with a small quantity of water, and titrate with 0.01 N sulfuric acid. Each milliliter of 0.01 N acid is equivalent to 140 p.g of nitrogen. 

It is a white, crystalline solid, very deliquescent, freely soluble in water, and moderately soluble in alcohol. When exposed to air it evolves hydrogen sulphide,1 and is completely decomposed by heat into this gas and sodium monosulphide.2 The anhydrous salt is also obtained by the interaction at 300° C. of sodium monosulphide and hydrogen sulphide free from carbon dioxide and oxygen.3 Sabatier s4 method is to saturate a solution of sodium sulphide with hydrogen sulphide, and concentrate in an atmosphere of the same gas. A solution can be obtained by saturating sodium-hydroxide solution with hydrogen sulphide. A dihydrate and a trihydrate have been described.5... 

Potassium hydroxide, KOH.—The hydroxide can be prepared by methods similar to those employed for the corresponding sodium derivative. The chief processes are the electrolysis of the chloride, and the interaction of the carbonate or sulphate11 in aqueous solution with slaked lime. In the sulphate process, evaporation of the mother-liquid yields the anhydrous hydroxide, the monohydrate, or the di-hydrate, the formation of each product depending on the concentration.12 For laboratory use, the substance can be prepared free from carbonate by a method described by Jorissen and Filippo.13... 

Electrolytic Decomposition of Water. This industrial process is economically feasible in localities where low-cost electricity is available, where there is a demand for oxygen as well as for hydrogen, and where the hydrogen is required to be completely free from carbon compounds. Sodium and potassium hydroxides are the practicable electrolytes in this process. 

J ) Pass carbon dioxide free from acid through a weak solution of sodium hydroxide (or potassium hydroxide) for several minutes. Add a few drops of hydrochloric acid to a portion of file liquid. Describe and explain the result, testing the main product of the action, if necessary. In what essential respect does the compound formed from the sodium hydroxide differ from the one formed from calcium hydroxide ... 

Alkali-soluble Substances, The methods vary somewhat in detail. The following conditions are given by Landon. Five g. of dried cellulose is placed in a litre flask, and 300 c.c. of 10 per cent, potassium hydroxide solution (or the equivalent of sodium hydrosude) added. The hydroxides should be free from carbonate. The mixture is boiled under a reflux condenser for three hours. The ebullition should be as t... 

When determining sensitivity with alkali, the water used for diluting should be completely free from carbon dioxide. Otherwise too low a sensitivity is found. It is obvious from the above data that azolitmin paper prepared from 0.1 % indicator solution is the most sensitive reagent paper for strong acids and bases. The presence of 10 N hydrochloric acid and sodium hydroxide can be demonstrated readily with this paper. It is best also for weaker acids and bases. 

Transfer 30 g. of the hydrochloride to a 500 ml. separatory funnel, add 100 ml. of water and shake until a thin paste of uniform consistency is obtained add 10 per cent, aqueous sodium hydroxide solution in the cold with shaking until the whole mass has become bright green (the colour of the free base) and the mixture has an alkaUne reaction. Extract the free base by shaking with two 60 ml. portions of benzene (1). Dry the combined benzene extracts with a Uttle anhydrous potassium carbonate, and filter into a distiUing flask fitted with a water condenser. Distil off about half of the benzene, and pour the residual hot benzene solution into a beaker. Upon cooUng, the p-nitrosodimethylaniUne erystallises in deep green leaflets. Filter these off and dry them in the air. The yield of p-nitrosodimethylaniUne, m.p. 85°, from the hydrochloride is almost quantitative. 

To isolate the triphenylguanidine, dilute the residue in the flask with 50 ml. of water, add 2-3 g. of decolourising carbon, warm, and filter. Cool the solution in ice, and filter oflF the hydrochloride at the pump. Dissolve it in the minimum volume of hot water, render the solution alkaline with sodium hydroxide, and allow to cool. Filter off the free base (triphenylguanidine), and recrystallise it from alcohol it separates in colourless crystals, m.p. 144°, The yield is 3 g. 

Hydrolysis of a sulphonamide. Mix 2 g. of the sulphonamide with 3-5 ml. of 80 per cent, sulphuric acid in a test-tube and place a thermometer in the mixture. Heat the test-tube, with frequent stirring by means of the thermometer, at 155-165° until the solid passes into solution (2-5 minutes). Allow the acid solution to cool and pour it into 25-30 ml. of water. Render the resulting solution alkaline with 20 per cent, sodium hydroxide solution in order to liberate the free amine. Two methods may be used for isolating the base. If the amine is volatile in steam, distil the alkaline solution and collect about 20 ml. of distillate extract the amine with ether, dry the ethereal solution with anhydrous potassium carbonate and distil off the solvent. If the amine is not appreciably steam-volatile, extract it from the alkaline solution with ether. The sulphonic acid (as sodium salt) in the residual solution may be identified as detailed under 13. 

Sodium Chloroacetate Sodium chloroacetate [3926-62-3] mol wt 116.5, C2H2C102Na, is produced by reaction of chloroacetic acid with sodium hydroxide or sodium carbonate. In many appHcations chloroacetic acid or the sodium salt can be used interchangeably. As an industrial intermediate, sodium chloroacetate may be purchased or formed in situ from free acid. The sodium salt is quite stable in dry soHd form, but is hydrolyzed to glycoHc acid in aqueous solutions. The hydrolysis rate is a function of pH and temperature (29). 

Recovery of Ammonia. The filter Hquor contains unreacted sodium chloride and substantially all the ammonia with which the brine was originally saturated. The ammonia may be fixed or free. Fixed ammonia (ammonium chloride [12125-02-97]) corresponds stoichiometrically to the precipitated sodium bicarbonate. Free ammonia includes salts such as ammonium hydroxide, bicarbonate, and carbonate, and the several possible carbon—ammonia compounds that decompose at moderate temperatures. A sulfide solution may be added to the filter Hquor for corrosion protection. The sulfide is distilled for eventual absorption by the brine in the absorber. As the filter Hquor enters the distiller, it is preheated by indirect contact with departing gases. The warmed Hquor enters the main coke, tile, or bubble cap-fiUed sections of the distiller where heat decomposes the free ammonium compounds and steam strips the ammonia and carbon dioxide from the solution. 

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