Iron ammonium alum

This solution is then diluted and titrated with standard potassium thiocyanate solution, using ammonium iron alum as indicator.1... 

Dissolve 100 g. of iron alum (ferric ammonium sulphate) in 300 ml. of water at 65°, Pour the solution, with stirring, into a solution of 25 g. of hydroquinone in 100 ml, of water contained in a 600 ml. beaker. The quinhydrone is precipitated in fine needles. Cool the mixture in ice, filter with suction, and wash three or four times with cold water. Dry in the air between filter paper. The yield of quinhydrone, m.p, 172°, is 15 g. It contains a trace of iron, but this has no influence upon the e.m.f, of the quinhydrone electrode provided that the washing of the crude material has been thorough. The quinhydrone should be stored in a tightly-Btoppered bottle. 

Azninon-. ammonium ammonia, -alaun, m. ammonia alum, ammonium alum, -chlorid, n. ammonium chloride. -eisenalaun, m. unmonium iron alum. -formiat, n. ammonium formate. 

Eisen-alaun, m. iron alum (ferric potassium sulfate), -amiant, m. (Iron) fibrous silica.. ammonaiauQ, m. ammonium ferric alum.. ammonaiaunldsuQg, /. solution of ammonium iron salt, esp. ammonium ferric alum. -antimonerZ) n., -antimonglanz, m. berthier-ite. 

F-test 140, (T) 841 Faraday constant 60, 504 Faraday s laws 503, 504 Fast sulphon black F 319 Fats D. of saponification value, (ti) 308 Ferric alum indicator see Ammonium iron(III) sulphate... 

Synonyms ferric ammonium sulfate ammonium ferric sulfate iron alum ferric alum ferric ammonium alum... 

An intimate mixture ot 274 grms. of rubidium iron alum, or 260 grms. of rubidium aluminium alum with 100 grms. of calcium carbonate, and 27 grms. of ammonium chloride, is heated in a nickel crucible to a dull red heat until ammonia vapours are no longer evolved, and then the temp, is raised to redness. The product is ground with a litre of cold water for 15 minutes filtered by suction and washed with 400 c.c. of water, added in small portions at a time. The combined sulphuric acid is precipitated by the addition of barium hydroxide, and the filtered liquid boiled while a stream of carbon dioxide is passed through the soln. If the soln. loses its alkaline reaction, and yet retains some calcium, a little rubidium carbonate must be added to precipitate calcium carbonate. The soln. is then treated with hydrochloric acid and evaporated. 

As a preliminary, ferric sulfate is made by the oxidation of ferrous sulfate. Dissolve 100 g. of ferrous sulfate in 100 cc. of boiling water, to which has been added before heating 10 cc. of sulfuric acid. Add concentrated nitric acid portionwise to the hot solution, until a diluted sample gives a reddish-brown (not black) precipitate with ammonia. This will require about 25 cc. Boil the solution down to a viscous liquid to get rid of excess nitric acid, dilute to about 400 cc., and add the calculated weight of ammonium sulfate. The crystallization is conducted as in the former exercise, preferably under 20°. By the addition of potassium sulfate, the corresponding potassium iron alum may be secured. In this case, it is necessary to concentrate the solution until there is about four parts of water to one of the hydrated alum and cool to about zero to secure crystallization. Both of these alums are amethyst in color, the potassium salt being much less stable and having a rather low transition point. 

Chemical properties of iron. Passivity. Ferrous compounds ferrous sulfate, ferrous ammonium sulfate, ferrous chloride, ferrous hydroxide, ferrous sulfide, ferrous carbonate. Ferric compounds ferric nitrate, ferric, sulfate, iron alum, ferric chloride, ferric hydroxide, ferric oxide (rouge, Venetian red). Potassium ferro-cyanide, potassium ferricyanide, Prussian blue. 

Alum 10043-01-3 Ammonium Iron Sulfate 10045-89-3 Antimony Trifluoride 7783-56-4... 

In a back-titration of silver by chloride ions, potassium chromate can be used to indicate the endpoint (Mohr s method) but with potassium thiocyanate as titrant, ammonium iron(III) sulfate ( ferric alum ) is preferred. In the direct titration (Gay-Lussac s method) the location of the turbidimetric endpoint has been improved in detail. ... 

AMMONIUM IRON SULPHATE (Alum) (NH4)2Fe2(S04)4.24H20. 

The octahedral, cubic crystals are violet to black in colour, and appear ruby-red in thin layers and J. H. Kastle found that the intensity of the colour is very much reduced at liquid air temp. F. Klocke, C. F. Rammelsberg, C. von Hauer, and J. W. Retgers showed that the crystals are isomorphous with other alums, for they show similar corrosion figures. E. Dittler obtained overgrowth with potassium aluminium sulphate. T. V. Barker found a close connection between parallel overgrowths in chrome-alum, potash-alum, and ammonia-alum and the mol. vols which are respectively 542-2, 541-6, and 552-2. C. von Hauer found that with the introduction of a crystal of iron-alum in a sat. soln. of chrome-alum nearly all the latter separates out while L. de Boisbaudran found that a sat. soln. of basic ammonium aluminium alum does not affect the octahedral faces of the... 

A more refined test is the Schultz (1924) method for cholesterol, which involves the application of a mixture of concentrated sulfuric acid and glacial acetic acid to sections which have been oxidized with ferric ammonium sulfate (iron alum). A blue-green color results. The iron alum apparently oxidizes 3-hydroxy steroids and their esters to 7-oxy steroids, which give the Lifschlltz color reaction on the application of the acids. (Fieser and Fieser, 1949, p. 234). This test is considered to be more specific for a limited group of steroids than is the sulfuric acid method cited above, which reveals a large number of unsaturated polycyclic compounds. Recently, however, Kent (1952) has reported that a positive reaction also occurs with carotene. 

Huber and Van der Wielen determine the volatile oil (thiocyanate) in mustard seeds as follows. Their experiments were directed towards determining to what extent the time of maceration of the crushed seeds in water influences the result. Five gram samples of the mustard were macerated for 1, 2, 4, 18, and 20 hours respectively, with 100 c.c. of water, after which were added 20 c.c. of alcohol and 2 c.c. of olive oil. Of the mixture about 50 c.c. were distilled into a 100 c.c. measure containing 10 c.c. of ammonia, taking care that the delivery tube was immersed in the ammonia. After adding 20 c.c. of deci-normal silver nitrate solution the whole was heated over a water-bath until the silver sulphide had aggregated and the liquid was clear. The liquid was then cooled and made up with water to 100 c.c., the excess of silver nitrate was determined by titration with deci-normal ammonium thiocyanate, usW iron alum as an indicator. 

Indicator solution. Dissolve 40 g of ammonium iron(III) sulphate dodecahydrate (ferric alum) in a mixture of 20 cm of nitric acid water (3 5 v.v) and 80 cm of water. Heat to boiling and dilute with 3 volumes of water. 

Boil about 10 g, accurately weighed, under reflux with 20 ml of 5 per cent ethanolic solution of sodium hydroxide for thirty minutes. Add 100 ml of water, acidify with dilute nitric acid and add 10 ml of O IN silver nitrate. Shake vigorously, filter, wash and titrate with 0-02N ammonium thiocyanate using iron alum as indicator. 1 ml 0 1 N AgN03 = 0 03545 g CijHyCl,. 

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