Sodium nitrate, solubility

Sodium is not found ia the free state ia nature because of its high chemical reactivity. It occurs naturally as a component of many complex minerals and of such simple ones as sodium chloride, sodium carbonate, sodium sulfate, sodium borate, and sodium nitrate. Soluble sodium salts are found ia seawater, mineral spriags, and salt lakes. Principal U.S. commercial deposits of sodium salts are the Great Salt Lake Seades Lake and the rock salt beds of the Gulf Coast, Virginia, New York, and Michigan (see Chemicals frombrine). Sodium-23 is the only naturally occurring isotope. The six artificial radioisotopes (qv) are Hsted ia Table 1 (see Sodium compounds). 

Hitec Heat-Transfer Salt. Hitec heat-transfer salt, manufactured by Coastal Chemical Co., is an eutectic mixture of water-soluble inorganic salts potassium nitrate (53%), sodium nitrite (40%), and sodium nitrate (7%). It is suitable for Hquid-phase heat transfer at temperatures of 150—540°C. 

Selected physical and chemical properties of sodium nitrate are Hsted in Table 1. At room temperature, sodium nitrate is an ododess and colodess soHd, moderately hygroscopic, saline in taste, and very soluble in water, ammonia, and glycerol. Detailed physical and chemical properties are also available (3,4). 

Ammonium chloroplatinate often can be used to advantage in place of chloroplatim c acid in the preparation of Adams catalyst. A mixture of 3 g. of ammonium chloroplatinate and 30 g. of sodium nitrate in a casserole or Pyrex beaker is heated gently at first until the rapid evolution of gas slackens and then more strongly until a temperature of 500° is reached. This operation requires about fifteen minutes and there is no spattering. The temperature is held at 500-520° for one-half hour and the mixture is then allowed to cool. The platinum oxide catalyst, collected in the usual way by extracting the soluble salts with water, weighs 1.5 g. and it is comparable in appearance and in activity to the material prepared from chloroplatinic acid. 

Anionic and neutral polymers are usually analyzed successfully on Syn-Chropak GPC columns because they have minimal interaction with the appropriate mobile-phase selection however, cationic polymers adsorb to these columns, often irreversibly. Mobile-phase selection for hydrophilic polymers is similar to that for proteins but the solubilities are of primary importance. Organic solvents can be added to the mobile phase to increase solubility. In polymer analysis, ionic strength and pH can change the shape of the solute from mostly linear to globular therefore, it is very important to use the same conditions during calibration and analysis of unknowns (8). Many mobile phases have been used, but 0.05-0.2 M sodium sulfate or sodium nitrate is common. 

TABLE 20.7 Conformational Coefficients for Water-Soluble Polymers in 0.05 N Sodium Nitrate with TSK-PW Columns... 

Explain how fractional crystallisation may be applied to a mixture of sodium chloride and sodium nitrate, given the following data. At 290 K, the solubility of sodium chloride is 36 kg/100 kg water and of sodium nitrate 88 kg/100 kg water. Whilst at this temperature, a saturated solution comprising both salts will contain 25 kg sodium chloride and 59 kg sodium nitrate/100 parts of water. At 357 K these values, again per 100 kg of water, are 40 and 176, and 17 and 160 kg respectively. 

The same reaction can be applied, not only to the aromatic parent substances, the hydrocarbons, but also to all their derivatives, such as phenols, amines, aldehydes, acids, and so on. The nitration does not, however, always proceed with the same ease, and therefore the most favourable experimental conditions must be determined for each substance. If a substance is very easily nitrated it may be done with nitric acid sufficiently diluted with water, or else the substance to be nitrated is dissolved in a resistant solvent and is then treated with nitric acid. Glacial acetic acid is frequently used as the solvent. Substances which are less easily nitrated are dissolved in concentrated or fuming nitric acid. If the nitration proceeds with difficulty the elimination of water is facilitated by the addition of concentrated sulphuric acid to ordinary or fuming nitric acid. When nitration is carried out in sulphuric acid solution, potassium or sodium nitrate is sometimes used instead of nitric acid. The methods of nitration described may be still further modified in two ways 1, the temperature or, 2, the amount of nitric acid used, may be varied. Thus nitration can be carried out at the temperature of a freezing mixture, at that of ice, at that of cold water, at a gentle heat, or, finally, at the boiling point. Moreover, we can either employ an excess of nitric acid or the theoretical amount. Small scale preliminary experiments will indicate which of these numerous modifications may be expected to yield the best results. Since nitro-compounds are usually insoluble or sparingly soluble in water they can be precipitated from the nitration mixture by dilution with water. 

Explain how fractional crystallisation may be applied to a mixture of sodium chloride and sodium nitrate given the following data. At 293 K, the solubility of sodium chloride is 36 kg/100 kg water... 

Figure 15.35. Effect of sodium chloride on the solubility of sodium nitrate...

With all solvents studied including cyclohexanol, methyl ethyl ketone and cyclohexanone, heptavalent technetium is extracted most effectively from sodium sulfate and weakest from sodium nitrate or sodium perchlorate solutions. The data in Fig. 5 appear to be consistent with those on the solubilities of various sodium salts in pure tri-H-butyl phosphate. For example, the solubility of Na SO in TBP is extremely small compared with NaClO. ... 

The general effect of the presence of a salt in soln. is to reduce the solubility of bromine,30 and this the more the greater the cone, of the salt. For example, with a j-yV-soln. of sodium nitrate, 3 374 grms. of bromine were dissolved per 100 c.c., and with a iV-soln., 2 88 grms., while the solubility of bromine in water at 25° is 3-395 grms. per 100 c.c. The effect of a few typical salts, in grms. per 100 c.c., on the solubility of bromine—grams per 100 c.c.—in water is as follows ... 

Sodium carbonate is obtained by adding sodium nitrate to the mother liquid which after the separation of the potassium nitrate corresponded with P2 this carries the point representing the composition of the soln. along P2Pi towards P3. At P2 there is practically no sodium nitrate in soln., and when this salt is added, the solubility of the sodium carbonate is lowered, from 37 7 grms. per litre... 

The terminal numbers with potassium, rubidium, and csesium nitrates represent the b.p. of sat. soln. at nearly normal press. for sodium nitrate the corresponding value is 67 6 (119°). Determinations of the solubility of sodium nitrate have been made by G. J. Mulder, Earl of Berkeley, A. Ditte, L. Maumene, A. fitard, etc.30 The solubility curve of sodium nitrate has been carried upwards 781 (180°), 83 5 (220°), 915 (225°), and 100 (313°), the last-named temp, represents the m.p. of the salt. According to L. C. de Coppet, the eutectic or cryohydric temp, of sodium nitrate is —18"5°, and the eutectic mixture is not a definite hydrate, NaN03.7H20, as A. Ditte once supposed. A. fitard represents the solubility S... 

Sodium and potassium nitrates are soluble in liquid ammonia,38 and the soln. are good electrical conductors. According to F. M. Raoult, the dry salts absorb no ammonia, but a cone. soln. of sodium nitrate dissolves as much ammonia as an equal volume of water, and a cone. soln. of potassium nitrate, more ammonia than water. R. Abegg and H. Riesenfeld found the tension of N, N-, and l 5A-soln. of potassium nitrate in A-soln. of ammonia at 25°, had vap. press. 14 59, 15 61, and 16 75 mm. respectively, when the A-ammonia alone had a vap. press, of 13 45 mm. F. Ephraim prepared lithium tetrammino-nitrate, LiN03.4NH3, as a syrup more stable than the corresponding tetrammino-chloride. The electrical conductivities and the lowering of the f.p. of soln. of potassium nitrate 39 in soln. 

---