Sodium iodate iodide

Iodine occurs to a minute extent (less than 0.001 %) in sea water, but is found in greater concentration, combined in organic form, in certain seaweeds, in oysters and in cod livers. Crude Chile saltpetre, or caliche contains small amounts of sodium iodate, NalOj. from which iodine can be obtained (see below). Some insoluble iodides, for example liiose of silver and mercury(II), occur in Mexico. Iodine is found in the human body in the compound thyroxin in the thyroid gland deficiency of iodine in diet causes enlargement of this gland (goitre). 

Most iodine produced commercially comes from the sodium iodate(V) remaining after sodium nitrate has been crystallised from Chile saltpetre. The iodatefV) is first reduced to iodide by blowing sulphur dioxide into the solution (or by addition of sodium sulphite) ... 

Tin ores and concentrates can be brought into solution by fusing at red heat in a nickel cmcible with sodium carbonate and sodium peroxide, leaching in water, acidifying with hydrochloric acid, and digesting with nickel sheet. The solution is cooled in carbon dioxide, and titrated with a standard potassium iodate—iodide solution using starch as an indicator. 

The hydrogen ions thus set free can be titrated with a standard solution of sodium hydroxide using an acid-base indicator or a potentiometric end point alternatively, an iodate-iodide mixture is added as well as the EDTA solution and the liberated iodine is titrated with a standard thiosulphate solution. 

Self-Test K.3B When sulfuric acid reacts with sodium iodide, sodium iodate and sulfur dioxide are produced. Identify the oxidizing and reducing agents in this reaction. 

In order to shift the equilibrium to the right-hand-side (i.e., towards As205) in the above reaction, sodium bicarbonate (NaHC03) is employed to remove the HI generated. It is important to record here that neither sodium hydroxide nor sodium carbonate can be used as both of them produce sodium iodide (Nal) and sodium iodate (NaI03) as designated below ... 

Iodine is produced in large scale from Chilean nitrate. Iodine occurs in this mineral as sodium iodate, NalOs. The iodate extract of the mineral becomes more concentrated in iodate after sodium nitrate crystaUizes out. The mother liquor is then treated with sodium bisulfite solution to give sodium iodide ... 

Formerly all the iodine was made from the ash of seaweed, and potash was a remunerative appendix to the iodine industry but just as the Stassfurt salts killed those industries which extracted potash from other sources, so did the separation of iodine from the caliche mother-liquors threaten the industrial extraction of iodine from seaweed with extinction. Iodine in a very crude form was exported from Chili in 1874—e.g. a sample was reported with iodine 52-5 per cent. iodine chloride, 3-3 sodium iodate, 13 potassium and sodium nitrate and sulphate, 15 9 magnesium chloride, 0 4 insoluble matter, 1 5 water, 25-2 per cent. About that time much of the iodine was imported as cuprous iodide. This rendered necessary the purification of the Chilian product but now the iodine is purified in Chili before it is exported. The capacity of the Chilian nitre works for the extraction of iodine is greater than the world s demand. It is said that the existing Chilian factories could produce about 5100 tons of iodine per annum whereas the... 

Sodium iodate dissolves copiously in warm dil. sulphuric acid without decomposition but it is decomposed by hydrochloric acid. The presence of potassium iodide causes potassium iodate to dissolve more readily than in pure water and although A. Ditte says that a double salt is not obtained from the soln., yet the phenomenon is probably due to the formation of a complex salt in soln. J, N. Bronsted measured the solubility of potassium iodate in aq. soln. of potassium hydroxide. Potassium iodate does not dissolve in alcohol. According to H. L. Wheeler, 100 grms. of water at 23° dissolve 21 grms. of rubidium iodate, and 26 grms. of caesium iodate at 24°. The specific gravity of a sat. aq. soln. of lithium iodate 52 at 18° is 1 568 thesp. gr. of soln. of potassium iodate calculated by G. T. Gerlach. from P. Kremers data, are ... 

Sodium hypophosphite , see Sodium phosphinate, 4467 Sodium iodate, 4619 Sodium iodide, 4618 Sodium isopropoxide, 1266... 

P 35] A reaction system with two competitive parallel reactions was used for mixing characterization [36], The Dushman reaction involves the mixing of iodate, iodide and sodium acetate in one solution and a strong acid such as sulfuric acid or hydrochloric acid in another solution. If mixing is fast, the neutralization of the acid and the base dominates as the faster reaction. The redox reaction of iodide and iodate then is a slow process nearly no iodine is formed as the redox product... 

Crystalline paraperiodic acid, H5I06, which is hygroscopic and readily soluble in water, is commercially available. Most of the salts of periodic acid are characterized by their slight solubility in water. For oxidation experiments sodium metaperiodate, NaIC>4, is the most suitable salt because of its solubility in water (9.3% at 20° and 12.6% at 25°).99 Sodium metaperiodate is commercially available and also can be obtained readily from the slightly soluble trisodium paraperiodate, Na3H2I06, by crystallization from nitric acid in the ratio of 150 cc. of water and 45 cc. of concentrated nitric add to 100 g. of salt.9 Trisodium paraperiodate is formed in 90% yield by the reaction of bromine and sodium iodide in aqueous sodium hydroxide solution at 80°.100 It is also produced in 80% yield by the oxidation of sodium iodate with chlorine in aqueous sodium hydroxide solution.99 In connection with this preparation of trisodium paraperiodate from sodium iodate, it should be noted that in the usual periodate oxidation reactions the periodate is converted quantitatively into iodate. Paraperiodic acid has been prepared in about 93% yield from trisodium paraperiodate " 1 it has been prepared also by the electrolytic oxidation 191 >192 of iodic add. 

The electrolysis is best performed as follows A solution of 13-15 g. calcined soda and 10 g. potassium iodide in 100 cc. water and 20 cc. alcohol is placed in a porous earthenware cylinder with platinum anode. The cathode, of nickel, is surrounded by a strong solution of sodium hydroxide. The electrolysis is carried out at a temperature of 70° C., with a current density at the anode of 1 amp. per 100 sq. cm., and is continued for 2-3 hours. After several hours the iodoform crystallizes out, the current yield being from 60-70 per cent. The chief by-product remaining in the mother liquor is sodium iodate. 

Sodium iodate, NaI03.—The iodate is a constituent of Chile saltpetre or sodium nitrate, and remains in the mother-liquor after crystallization of the nitrate. It is an important source of iodine. The salt can be prepared by oxidizing sodium iodide with sodium peroxide6 or by the electrolytic method,7 and also by the interaction of sodium iodide and periodate.8 It forms white crystals. 

Iodine is conveniently made in the laboratory from sodium iodide, by the method described above for making bromine from a bromide. Commercial iodine is made from tl e sodium iodate present as an impurity in Chile saltpeter, from oil-well brines, and from sea weed (kelp). 

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