Sodium iodide test

Label a series of ten clean and dry test tubes from 1 to 10, as described in the previous section. Add 2 mL of a 1% ethanolic silver nitrate solution to each test tube. Now add 4 drops of the appropriate halide to each test tube, using the same numbering scheme indicated for the sodium iodide test. To avoid cross-contaminating these halides, return the dropper to the proper container. 

Sodium Iodide Test for Alkyl Chlorides and Bromides... 

Apply the test to compounds which contain chlorine or bromine. If the compound is a solid, dissolve 0 1 g. in the minimum volume of pure, dry acetone. To 1 ml. of the sodium iodide acetone reagent add 2 drops of the compound (if a hquid) or the acetone solution (if a sohd). Shake and allow to stand at room temperature for 3 minutes. Note whether a precipitate is formed and also whether the solution acquires a reddish-brown colour (liberation of iodine). If no change takes place at rocrm temperature, place the test-tube in a beaker of water at 50°. After 5 minutes, cool to room temperature, and observe whether a reaction has occurred. 

Iodine. Iodine has been important for many years, primarily as an antiseptic (see Iodine and iodine compounds). In the American Civil War physicians used it to treat battie wounds. Elemental iodine is not very soluble in water, but dissolves readily when sodium iodide is added, forming triiodide + I I Iodine may thus be used as an aqueous solution but it has generally been used as a tincture of 2% iodine in 70% alcohol. Tests on... 

The molecular absoi ption spectra, registered at a lower temperature (e.g. 700 °C for iodide or chloride of potassium or sodium), enable one to find the absorbance ratio for any pair of wavelengths in the measurement range. These ratios can be used as a correction factor for analytical signal in atomic absoi ption analysis (at atomization temperatures above 2000 °C). The proposed method was tested by determination of beforehand known silicon and iron content in potassium chloride and sodium iodide respectively. The results ai e subject to random error only. 

Sodium -toluenesulfonate, 3, 37, 38 Splitting C C linkage, 4, 39 Splitting C Hg linkage, 7, 19 Stabilizer, 8, 56 Stannous chloride, 8, 96 Starch-iodide test 3, 7 79, 8, 42, 80 Steam distillation apparatus, 2, 0 Steam distillation, reduced pressure, 5, 80... 

To make a peroxide test, place a few milligrams of sodium iodide, a trace of ferric chloride, and 2-3 ml. of glacial acetic acid in a test tube and carefully add 1-2 ml. of the ether 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. 

Halide exchange, sometimes call the Finkelstein reaction, is an equilibrium process, but it is often possible to shift the equilibrium." The reaction is most often applied to the preparation of iodides and fluorides. Iodides can be prepared from chlorides or bromides by taking advantage of the fact that sodium iodide, but not the bromide or chloride, is soluble in acetone. When an alkyl chloride or bromide is treated with a solution of sodium iodide in acetone, the equilibrium is shifted by the precipitation of sodium chloride or bromide. Since the mechanism is Sn2, the reaction is much more successful for primary halides than for secondary or tertiary halides sodium iodide in acetone can be used as a test for primary bromides or chlorides. Tertiary chlorides can be converted to iodides by treatment with excess Nal in CS2, with ZnCl2 as catalyst. " Vinylic bromides give vinylic iodides with retention of configuration when treated with KI and a nickel bromide-zinc catalyst," or with KI and Cul in hot HMPA." ... 

The perchlorate ion of potassium perchlorate, KCIO4, is a competitive inhibitor of thyroidal 1 transport via the Sodium Iodide Symporter (NIS).This drug can cause fatal aplastic anemia and gastric ulcers and is now rarely used. If administered with careful supervision, in limited low doses and for only brief periods, serious toxic effects can be avoided. The compound is especially effective in treating iodine-induced hyperthyroidism, which may occur, for example, in patients treated with the antiar-rhythmic compound amiodarone. Perchlorate ion can also be used in a diagnostic test of 1 incorporation into Tg, the so-called perchlorate discharge test. 

Before injection, monitoring probes re placed on the outlet lines close a the exit from the tank being tested. These probes consist of a l-in.-diarr.-tter, thalium-activated sodium-iodide scintillation crystal, a small portable meter, and a recorder. 

One sulfonylated aldonic-acid derivative of this type has been tested, viz., methyl 2,4 5,6-di-0-methylene-3-0-tosyl-n-gluconate. On treatment418 with sodium iodide-acetone at 100° it gave free iodine plus sodium p-toluenesulfonate (50%, 2 hours 57%, 4 hours). If heated with sodium iodide-acetic anhydride under reflux for 2 hours, a 98% yield of sodium p-toluenesulfonate resulted. What contribution the carbomethoxy group makes is, as yet, unknown but there is reason to believe181 that it may be considerable. 

The test consists in treating a solution of sodium iodide in pure acetone with the organic compound. The reaction is probably of the SN2 type involving a bi-molecular attack of the iodide ion upon the carbon atom carrying the chlorine or bromine the order of reactivities of halides is primary > secondary > tertiary and Br > Cl. 

General Rules of Solubility as listed in Chapter 8 0.1 M solutions of the following compounds (these are the unknown solutions) Ag(N03) (silver nitrate), Ca(N03)2 (calcium nitrate), Cu(N03)2 (copper nitrate), NaOH (sodium hydroxide), KC1 (potassium chloride), Na2SC>4 (sodium sulfate), Nal (sodium iodide), and Na3PC>4 (sodium phosphate) eight small test tubes eight small disposable pipets pH paper one flame test wire in a cork glass plates a Bunsen burner and 3M HC1 (hydrochloric acid). 

Immediately upon connecting the cell to a source of direct current, a deposit of gray metallic zinc appears on the surface of the cathode and bubbles of chlorine gas appear at the surface of the anode. A simple chemical test for chlorine may be made by leading this gas into an aqueous sodium iodide solution, whereupon the solution assumes a yellow color caused by displacement of iodine by chlorine. Accordingly, it is concluded that the products of the electrolysis of a zinc chloride solution are elemental zinc and elemental chlorine, and the next problem is that of explaining the mechanism by which these products may be produced. 

Chloro-5-(l -Chlorocyclohexyl)-2-Oxo-2,3-Dihydro-lH-Benzo[f]Diazepine-1,4 A solution of 117 grams of the compound prepared above in 450 ml ethyl acetate is heated under reflux until a precipitate begins to form. From then onwards reflux is continued until a negative reaction is obtained when the reaction mixture is tested with a solution of sodium iodide in acetone. The... 

Hydrogen Iodide. Add 1 cc. of 36 N sulphuric acid to 0.5 gram of powdered potassium or sodium iodide, and apply all the tests enumerated in Experiments 12 and 13 also inspect the walls of the test tube carefully to see if any solid sulphur condenses. 

Place about 0.5 gram of powdered sodium bromide in a test tube with a little concentrated phosphoric acid solution, heat, and test the evolved gas for free halogen as well as for hydrogen bromide. Repeat, using sodium iodide in place of the sodium bromide. 

In both experiments, fogging of the breath, reddening of litmus, and smoke with ammonia are noted. With the sodium bromide, the gas is entirely uncolored and no test with iodide starch paper is given. With sodium iodide the gas is at first entirely colorless but when the tube is heated strongly the film of moisture condensing on the walls of the tube becomes slightly brown. No test is given with starch paper. 

Sodium iodide is soluble in acetone, whereas both sodium chloride and sodium bromide are insoluble, so the appearance of a precipitate is a positive test for the presence of an alkyl chloride or bromide. 

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