Hydrosulphite potassium

Moissan in 1902 obtained anhydrous hydrosulphites by passing sulphur dioxide diluted with hydrogen over the hydrides of the alkali and alkaline earth metals.6 He was able to produce the hydrosulphites of sodium, potassium, lithium, calcium and strontium in this way, and by measurement of the quantity of hydrogen liberated was able to prove the correctness of the general formula Ma.S204 ... 

An iodometric method consists in estimating the iodine liberated from a mixture of potassium iodide and iodate,8 excess of which is added to the hydrosulphite solution, the reaction being according to the equation ... 

Selenium is soluble in sulphuric acid, forming a green solution which, in the case of the metallic form, probably contains a compound of composition S03Se (p. 338), and in the case of the red amorphous variety, a polymeric form of this compound.8 The presence of selenium does not affect the electrical conductivity of sulphuric aeicl. Dilute aqueous potassium hydroxide dissolves the red variety, producing a solution which probably contains polyselenides in the presence of sodium hydrosulphite, however, only sodium selenide, Na2Se, is obtained.9... 

F. Raschig mixed a mol of potassium nitrite dissolved in as little water as possible with a well-cooled soln. of 2 mols of potassium hydrosulphite, and added a cold sat. soln. of about 2 mols of potassium chloride. In 24 hrs., the needle-like crystals of nitrilosulphonate were separated from the crystalline crust of the nitrilo-disulphonate by washing. The latter salt can be purified by crystallization from warm water rendered alkaline by ammonia or potassium hydroxide. A. Claus also made the salt by mixing 4 mols of potassium sulphite and one of potassium nitrite. The soln. is filtered from the crystals of nitrilosulphonate, and in about 10-12 hrs. it deposits crystals of dipotassium nitrilodisulphonate. He also made the same salt by crystallization from a soln. of potassium nitrosyl sulphonate in warm water. 

Extraction of the elemental form of bromine is used to separate short-lived bromine activities from fission products. Potassium chlorate in 8 N nitric acid solution (255)s potassium permanganate in nitric acid solution (106,248), and a bromlde-bromate-hypofchlorite mixture in acidic solution (247) have been used as the oxidizing agent. The bromine is extracted into carbon tetrachloride and can be back-extracted into the aqueous solution by reducing agents, such as potassium nitrate (255)> hydrazine hydrochloride (106,248), or sodium hydrosulphite (106). 

A solution of 8-6 grams of 5-nitro-6-amino-j i-tolylarsinic add in 75 c.c. of water and 6 2 c.c. of lOAT sodium hydroxide solution is cooled to —1° C. and 20-4 grams of sodium hydrosulphite added in one oiJeration. When the reaction is complete the solution is filtered and 8-1 c.c. of hydrochloric acid (density 1 12) added. The arsinic acid separates and is recrystallised from water. It forms colourless needles, containing 1J to 2 mols. of water of crystallisation. It is soluble in methyl alcohol and acetic acid, sparingly soluble in ether, benzene, and petroleum. Its solution in dilute hydrochloric acid gives a chai acteristic deep violet coloration with a drop of dilute solution of potassium dichromate. 

This compound is derived from 2-nitro-8-aminophenylarsinic acid (p. 261), which, on boiling with concentrated potassium hydroxide, has its amino-grouj) replaced by hydroxyl, giving 2-nitro-8-hydroxyphenyl-arsinic acid. The latter, when reduced with sodium hydrosulphite, yields the arseno-compomid. 

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