Sulphur bicarbonate soluble

Study of the solubility behaviour of the compound. A semi-quantitative study of the solubility of the substance in a hmited number of solvents (water, ether, dilute sodium hydroxide solution, dilute hydrochloric acid, sodium bicarbonate solution, concentrated sulphuric and phosphoric acid) will, if intelligently apphed, provide valuable information as to the presence or absence of certain classes of organic compounds. 

Ck)ol the alkaline solution resulting from the distillation of the volatile neutral compounds, make it acid to litmus with dilute sulphuric acid, and add an excess of solid sodium bicarbonate. Extract this bicarbonate solution with two 20 ml. portions of ether remove the ether from the combined ether extracts and identify the residual phenol (or enol). Then acidify the bicarbonate solution cautiously with dilute sulphiu-ic acid if an acidic compound separates, remove it by two extractions with 20 ml. portions of ether if the acidified solution remains clear, distil and collect any water-soluble, volatile acid in the distillate. Characterise the acid as under 2. 

Separations based upon differences in the chemical properties of the components. Thus a mixture of toluene and aniline may be separated by extraction with dilute hydrochloric acid the aniline passes into the aqueous layer in the form of the salt, aniline hydrochloride, and may be recovered by neutralisation. Similarly, a mixture of phenol and toluene may be separated by treatment with dilute sodium hydroxide. The above examples are, of course, simple apphcations of the fact that the various components fall into different solubility groups (compare Section XI,5). Another example is the separation of a mixture of di-n-butyl ether and chlorobenzene concentrated sulphuric acid dissolves only the n-butyl other and it may be recovered from solution by dilution with water. With some classes of compounds, e.g., unsaturated com-poimds, concentrated sulphuric acid leads to polymerisation, sulphona-tion, etc., so that the original component cannot be recovered unchanged this solvent, therefore, possesses hmited apph cation. Phenols may be separated from acids (for example, o-cresol from benzoic acid) by a c ute solution of sodium bicarbonate the weakly acidic phenols (and also enols) are not converted into salts by this reagent and may be removed by ether extraction or by other means the acids pass into solution as the sodium salts and may be recovered after acidification. Aldehydes, e.g., benzaldehyde, may be separated from liquid hydrocarbons and other neutral, water-insoluble liquid compounds by shal g with a solution of sodium bisulphite the iddehyde forms a solid bisulphite compound, which may be filtered off and decomposed with dilute acid or with sodium bicarbonate solution in order to recover the aldehyde. 

Braude states, that the salts of magnesia are mostly soluble in water, and bitter they are all soluble in hydrochloric acid their aqueous solutions are precipitated by potassa and soda, the precipitate, being soluble In hydrochloric, nitric, and sulphuric acids, and in hydroohlorate, nitrate, and sulphate of ammonia. Ammonia only throws down part of the magnesia, and forms a double salt, and carbonates of potassa and soda only throw down part of the magnesia, except the solution be hentad, when pearly the whole is precipitated. Chloride of ammonium redissolves tiro deposit, and when previously added to the magnesian solution, no precipitate ensues on adding the alkaline carbonates, unless the liquor be warmed The bicarbonates of von. ir. 

Step 1. Extraction and separation of the acidic components. Shake 5-10 g. of the solid mixture (or of the residue S obtained after the removal of the solvent on a water bath) with 50 ml. of pure ether. If there is a residue (this probably belongs to Solubility Group II or it may be a polysaccharide), separate it by filtration, preferably through a sintered glass funnel, and wash it with a little ether. Shake the resulting ethereal solution in a small separatory funnel with 15 mL portions of 6 per cent, aqueous sodium hydroxide solution until aU the addic components have been removed. Three portions of alkali are usually sufiicient. Set aside the residual ethereal solution (Ej) for Stqt 2. Combine the sodium hydroxide extracts and wash the resulting mixture with 15-20 ml. of ether place the ether in the ETHER RESIDUES bottle. Render the alkaline extract acid to litmus with dilute sulphuric acid and then add excess of solid sodium bicarbonate. 

Weigh accurately into a 250-ml conical flask an amount of sample expected to contain from 0 08 to 0 09 g As. If (a) soluble in water, dissolve in 30 ml of water (b) insoluble in water, dissolve in 5 ml of N sodium hydroxide and 20 ml of water and add 5 ml of N sulphuric acid (c) containing chloride, dissolve in 50 ml of water. Place several glass beads in the flask and a small funnel in the neck, add 8 g of ammonium persulphate and boil briskly until colourless and for two minutes longer. (In the case of sodium cacodylate heat for about five minutes after ebullition commences.) Add cautiously 50 ml of approximately N oxalic acid and boil vigorously for five minutes. Add cautiously 40 ml of dilute sulphuric acid and 10 ml of potassium iodide solution. Boil vigorously until the volume is reduced to about 40 ml. Cool, just remove the pale yellow colour by the addition of approximately 01N sodium sulphite drop by drop (1 to 3 drops usually) and immediately add about 60 ml of water. Add 1 drop of phenolphthalein solution and sufficient sodium hydroxide test solution to render just alkaline. Add 10 ml of dilute sulphuric acid, mix, cool, neutralise with sodium bicarbonate, add up to 5 g in excess and titrate with 0 1 N iodine. If starch solution is used add it just before the end-point is reached. 

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