Sodium hydrogencarbonate

When heated, sodium hydrogencarbonate readily decomposes evolving carbon dioxide, a reaction which leads to its use as baking powder when the carhon dioxide evolved aerates the dough. In the soda-ammonia process the carbon dioxide evolved is used to supplement the main carbon dioxide supply obtained by heating calcium carbonate ... 

Lead(II) carbonate occurs naturally as cerussite. It is prepared in the laboratory by passing carbon dioxide through, or adding sodium hydrogencarbonate to. a cold dilute solution of leadfll) nitrate or lead(II) ethanoate ... 

A mixture of 4.0 grams of N-methyl-3-toluidine and 2.8 grams of sodium hydrogencarbon-ate in 50 cc of acetone was stirred at 0° to 10°C and 7.4 grams of 2-naphthyl chlorothiono-formate was added in small portions thereto and the mixture was heated under reflux for 30 minutes. The cooled mixture was poured into about 150 cc of cold water and 2-naphthvl-N-methvl-N-(3-tolyl)thionocarbamate was obtained as white crystals. Yield is 9.1 grams (90 o). Recrystallization from alcohol gave colorless needle crystals, MP 110.5° to 111.5°C. 

The same end point is reached by titrating sodium hydrogencarbonate solution with hydrochloric acid ... 

The end point with 100 mL of 0.2M sodium hydrogencarbonate and 0.2M hydrochloric acid may be deduced as follows from the known dissociation constant and concentration of the weak acid. The end point will obviously occur when 100 mL of hydrochloric acid has been added, i.e. the solution now has a total volume of 200 mL. Consequently since the carbonic acid liberated from the sodium hydrogencarbonate (0.02 moles) is now contained in a volume of 200 mL, its concentration is 0.1 M. Kl for carbonic acid has a value of 4.3 x 10 7, and hence we can say ... 

Either the Mohr titration or the adsorption indicator method may be used for the determination of chlorides in neutral solution by titration with standard 0.1M silver nitrate. If the solution is acid, neutralisation may be effected with chloride-free calcium carbonate, sodium tetraborate, or sodium hydrogencarbonate. Mineral acid may also be removed by neutralising most ofthe acid with ammonia solution and then adding an excess of ammonium acetate. Titration of the neutral solution, prepared with calcium carbonate, by the adsorption indicator method is rendered easier by the addition of 5 mL of 2 per cent dextrin solution this offsets the coagulating effect of the calcium ion. If the solution is basic, it may be neutralised with chloride-free nitric acid, using phenolphthalein as indicator. 

Procedure. Wdgh out accurately about 2.5g of finely powdered arsenic(III) oxide, transfer to a 500 mL beaker, and dissolve it in a concentrated solution of sodium hydroxide, prepared from 2g of iron-free sodium hydroxide and 20 mL of water. Dilute to about 200 mL, and neutralise the solution with 1M hydrochloric add, using a pH meter. When the solution is faintly add transfer the contents of the beaker quantitatively to a 500 mL graduated flask, add 2 g of pure sodium hydrogencarbonate, and, when all the salt has dissolved, dilute to the mark and shake well. 

Using a burette or a pipette with a safety pump (this is necessary owing to the poisonous properties of the solution) measure out 25.0 mL of the arsenite solution into a 250 mL conical flask, add 25-50 mL of water, 5g of sodium hydrogencarbonate, and 2 mL of starch solution. Swirl the solution carefully until the hydrogencarbonate has dissolved. Then titrate slowly with the iodine solution, contained in a burette, to the first blue colour. 

If it is desired to base the standardisation directly upon arsenic(III) oxide, proceed as follows. Weigh out accurately about 0.20 g of pure arsenic(III) oxide into a conical flask, dissolve it in 10 mL of 1M sodium hydroxide, and add a small excess of dilute sulphuric acid (say, 12-15 mL of 0.5M acid). Mix thoroughly and cautiously. Then add carefully a solution of 2 g of sodium hydrogencarbonate in 50 mL of water, followed by 2 mL of starch solution. Titrate slowly with the iodine solution to the first blue colour. Repeat with two other similar quantities of the oxide. 

This reaction is subject to a number of errors (1) the hydriodic acid (from excess of iodide and acid) is readily oxidised by air, especially in the presence of chromium(III) salts, and (2) it is not instantaneous. It is accordingly best to pass a current of carbon dioxide through the reaction flask before and during the titration (a more convenient but less efficient method is to add some solid sodium hydrogencarbonate to the acid solution, and to keep the flask covered as much as possible), and to allow 5 minutes for its completion. 

Procedure, (a) Place 25 mL of the chlorate solution (approx. 0.02M) in a glass-stoppered conical flask and add 3 mL of concentrated hydrochloric acid followed by two portions of about 0.3 g each of pure sodium hydrogencarbonate to remove air. Add immediately about 1.0 g of iodate-free potassium iodide and 22 mL of concentrated hydrochloric acid. Stopper the flask, shake the contents, and allow it to stand for 5-10 minutes. Titrate the solution with standard 0.1M sodium thiosulphate in the usual manner. 

For good results, the following experimental conditions must be observed (1) the hydrochloric acid concentration in the final solution should be at least 4M (2) air should be displaced from the titration mixture by adding a little solid sodium hydrogencarbonate (3) the solution must be allowed to stand for at least 5 minutes before the liberated iodine is titrated and (4) constant stirring is essential during the titration to prevent decomposition of the thiosulphate in the strongly acid solution. 

Treat the arsenate solution (say, 20.0 mL of ca 0.025M) in a glass-stoppered conical flask with concentrated hydrochloric acid to give a solution in 4M hydrochloric acid. Displace the air by introducing two 0.4 g portions of pure sodium hydrogencarbonate into the flask. Add 1.0 g of pure potassium iodide, replace the stopper, mix the solution, and allow to stand for at least 5 minutes. Titrate the solution, whilst stirring vigorously, with standard 0.1M sodium thiosulphate. 

Sodium hydrogencarbonate solution. Dissolve 4.2 g of the solid in 100 mL water. 

Sodium hydrogencarbonate was heated at a temperature of 100 C in the presence of carbon and water. During the handling, stirring was interrupted. When it started again a vioient release of carbon dioxide caused the content of the reactor to overflow. 

There was also a Cannizzaro reaction that gives rise to an accident. During a reaction that was carried out by using furfural this compound came into contact with sodium hydrogencarbonate that is used to check pHs. This compound catalysed a Cannizzaro reaction that couid not be controlied and caused the compounds to combust ... 

Plant samples are homogenized with sodium hydrogencarbonate aqueous solution to prevent decomposition of the analytes during homogenization. Imibenconazole and its primary metabolite, imibenconazole-debenzyl, are extracted from plan materials and soil with methanol. After evaporation of methanol from the extracts, the residues are extracted with dichloromethane from the residual aqueous solution. The dichloromethane phase is cleaned up on Florisil and Cig columns. Imibenconazole and imibenconazole-debenzyl are determined by gas chromatography/nitrogen-phosphorus detection (GC/NPD). 

Sodium hydrogencarbonate aqueous solutions, 10% (w/v) and saturated solution... 

Plant samples (1000 g) are homogenized using a blender with 10% aqueous sodium hydrogencarbonate solution (400 mL). The pH of the homogenates must be adjusted to 6-8 with saturated aqueous sodium hydrogencarbonate solution in this step. 

Transfer the residue derived from Section 6.1.1 or 6.1.2 into a 200-mL separatory funnel with 80 mL of water and add 5 g of sodium chloride. Adjust the pH of the aqueous phase to 6-8 with saturated aqueous sodium hydrogencarbonate solution. Extract the aqueous phase successively with 50 and 30 mL of dichloromethane by shaking the funnel with a mechanical shaker for 5 min. Combine the dichloromethane extracts and dry with anhydrous sodium sulfate. Transfer the extracts into a 100-mL round-bottom flask and concentrate the extracts to near dryness by rotary evaporation. Dissolve the residue in 2 mL of n-hexane. 

An unspecified process had been operated for 20 years using synthetic sodium carbonate powder (soda-ash) to neutralise the hydrogen chloride as it was formed by interaction of the amine and chloro compound in a non-aqueous (and probably flammable) solvent in a steel reactor. Substitution of the powdered sodium carbonate by the crystalline sodium carbonate-sodium hydrogencarbonate double... 

Following a published procedure [1], perchloric acid was used as catalyst in preparing a diol ketal, and was neutralised with sodium hydrogencarbonate before workup. Some sodium perchlorate remained dissolved after filtering the reaction mixture, and dining subsequent vacuum distillation (with the bath temperature increasing to 200°C) an explosion occurred. 

The reaction mixture was transferred into a separating funnel. The aqueous layer was extracted with dichloromethane (10 mL). The combined organic layers were washed with a aqueous solution of sodium hydrogencarbonate (2 x 20 mL), then with water (30 mL), dried over magnesium sulfate, filtered and the solvent removed under reduced pressure. 

A marked difference in the product pattern has been reported for the treatment of cellobiose with either NaOH or NaHCOs. The formation of 3-deoxy-2-0-(hydroxymethyl)pentonic acids (52) from cellobiose is less important in sodium hydrogencarbonate solution than in sodium hydroxide, while the relative amounts of 2-deoxytetronic, 3-deoxypentonic, and 3,4-dideoxypentonic acids are much larger. 

So the decomposition of sodium hydrogencarbonate just becomes feasible at 7-.J 385K... 

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