Potassium thiocyanate solution

IQ. To determine the concentration of chloride ion, - a 5-mL aliquot of the methyl lithium solution is cautiously added to 25 ml of water and the resulting solution is acidified with concentrated sulfuric acid and then treated with 2-3 ml of ferric ammonium sulfate [Fe(NH4)( 04)2 12 H2O] indicator solution and 2-3 ml of benzyl alcohol. The resulting mixture is treated with 10.0 mL of standard aqueous 0.100 M silver nitrate solution and then titrated with standard aqueous 0.100 H potassium thiocyanate solution to a brownish-red endpoint. 

Potassium thiocyanate solution. Prepare a 10 per cent aqueous solution from the pure salt. 

Potassium thiocyanate solution. Dissolve 20 g potassium thiocyanate in 100 mL water the solution is ca 2M. 

These and similar results can be explained if the simultaneous reduction of hydrogen peroxide is due to an induced reaction. To show the characteristic features of this reaction some results are presented in Table 19 and Table 20. The procedure for these measurements was as follows. The solution of peroxy compounds given in columns 1 and 2 was made up to 20 ml and the pH was adjusted to the given value. Then potassium thiocyanate solution was added and, after the reaction time noted, the process was quenched by adding potassium iodide solution (0.3 g KI). After 5 sec the solution was acidified with 1 ml 2 iV sulphuric acid then using, molybdate catalyst solution, the iodine liberated was titrated with standard thiosulphate. 

Pour 5 mL of iron(III) chloride and potassium thiocyanate solution into each of three clean test tubes. 

To the first test tube, add 1 mL of 0.1M potassium thiocyanate solution. Observe and record the color change in Data Table 1. 

Add to each funnel 2 ml of cone. HC1, 1 ml of ammonia iron (II) sulphate solution, and 3 ml of the potassium thiocyanate solution,... 

The mixture is tested for peroxide as follows Prepare an approximately 1% solution of ferrous ammonium sulfate. Transfer 5 ml to each of two test tubes and add 0.5 iriL of 0.5 M sulfuric acid and 0.5 iil. of 0.1 M potassium thiocyanate solution to each tube. Add 5 mL of the methylene chloride solution to one of the test tubes and shake well. The aqueous phase in the methylene chloride tube should not develop a brown red color when examined parallel to the blank. 

Addition of potassium thiocyanate solution forms a white precipitate of mercury(ll) thiocyanate ... 

Mercuric thiocyanate, which is formed as a white precipitate when mercuric nitrate and potassium thiocyanate solutions are mixed, is soluble in excess of either solution. When dried, this salt is inflammable, forming a voluminous ash known as Pharaoh s serpents. By the interaction of a mercuric salt with ammonium thiocyanate and thio-carbamide in acetic acid solution in the presence of an oxidising agent, or by the action of hydrogen sulphide on mercuric thiocyanate, the phototropic compound HS.Hg.CNS is obtained.6... 

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

The trichloride dissolves in liquid cyanogen.1 It combines with cyanogen bromide when a mixture of the two is slowly heated in an autoclave to 180° C., followed by cooling and keeping at 120° C. for one hour 2 the product, of composition AsCls.2BrCN, decomposes on heating above 190° C. Arsenic trichloride reacts with potassium thiocyanate solution,3 the latter being decomposed with liberation of ammonia, but no precipitate is produced, whereas both tin and antimony are precipitated as hydroxides under similar conditions the reaction with excess of potassium thiocyanate may be used to effect a quantitative separation of these two metals from arsenic. 

Treat a piece of starch paper successively with a drop of 01m potassium thiocyanate solution and a drop of the acid test solution. A blue spot is obtained. Sensitivity 3 pg IO3. Concentration limit 1 in 12,000. 

Place a drop of concentrated hydrochloric acid upon filter or drop-reaction paper and a drop of the test solution in the centre of the spot. A tungstate produces a yellow stain. Add a drop of 10 per cent potassium thiocyanate solution and a drop of saturated tin(II) chloride a red spot, due to [Mo(SCN)6]3 , is... 

Mix 0-5 ml of the test solution with 2 ml of 10 per cent potassium thiocyanate solution and 5 ml of 6m hydrochloric acid, and boil for 30 seconds. A red colouration, due to selenium, is produced. 

Experiment 189. — (a) Put a few grams (3 to 5) of iron filings in a test tube, add about 10 cc. of dilute hydrochloric acid, and warm gently. Ferrous chloride is formed (in solution), (i) Pour a little into a test tube one-third full of sodium hydroxide solution. The precipitate is ferrous hydroxide. Watch the changes in color. To what are the changes due (2) Add a second portion to potassium ferricyanide solution. The precipitate is ferrous ferricyanide. Describe it. (3) Add a third portion to potassium thiocyanate solution. If ferric salts are absent, no change results. (4) Add a fourth portion to potassium ferrocyanide solution. The precipitate is ferrous ferrocyanide. Describe it. 

Excess silver ions are then titrated with standard potassium thiocyanate solution in the presence of an iron (III) salt ... 

Both silver nitrate and potassium thiocyanate are obtainable in primary-standard quality. The latter is, however, somewhat hygroscopic, and thiocyanate solutions are ordinarily standardized against silver nitrate. Both silver nitrate and potassium thiocyanate solutions are stable indefinitely. 

Lin and Long [41] applied ELM to effectively separate nitrate ions (94% efficiency) from water with tri-n-octyl amine as the extractant and sodium carbonate as the internal phase. H+ ions were also transported along with NOs from external to the internal phase (cotransport). Kobya et al. [86] studied the kinetics of thiocyanate ion removal from aqueous potassium thiocyanate solution by counter-transport process using quaternary ammonium salt of hexadecyl trimethyl ammonium chloride as the cander and sodium chloride solution as the stripping phase. 

Figure 2. Thickness of DMS foam film formed from potassium thiocyanate solutions at various concentrations...

Figure 4. Electrophoretic mobility vs. log. Molar concentration of electrolyte for DMS stabilized dodecane droplets ( ) in sodium chloride solutions, (O) in potassium thiocyanate solutions.

Figure 7. Curves of surface pressure vs. area per molecule for films of OMS on potassium thiocyanate solutions (O) 10 4 mole/dm3 (A)...

The films formed from potassium thiocyanate solutions behaved differently from those formed from sodium chloride solutions. At the lowest salt concentration examined, 4 X 10"4 mole/dm3, the film had a thickness of 975 A, clearly a first black film. With increasing salt concentration the film thickness decreased and reached 60 A at a thiocyanate concentration of 5 X 10 1 mole/dm3 it remained at this thickness as the salt concentration was increased to 1 mole/dm3. This corresponded to the second black film thickness obtained with the films in sodium chloride solutions, and in this state the films were quite stable. The considerably thicker films formed in the presence of the thiocyanate ion indicate a stronger double layer repulsion effect than with chloride and hence a stronger adsorption of the thiocyanate ion to the film surface. These re-... 

A second example of this type of indicator is illustrated in the Volhard titration. This is an indirect titration procedure for determining anions that precipitate with silver (Cl , Br , SCN"), and it is performed in acid (HNO3) solution. In this procedure, we add a measured excess of AgNOa to precipitate the anion and then determine the excess Ag" " by back-titration with standard potassium thiocyanate solution ... 

Test a portion of the product for iron by heating it with concentrated sulfuric acid in a platinum crucible to drive off hydrofluoric acid then cool, dilute with water, and add potassium thiocyanate solution. (A lead dish and 70 per cent sulfuric acid may be used instead of the platinum crucible.) There should not be more than a faint orange reaction to indicate the presence of ferric iron. With the recrystallized material there should be no reaction at all. 

Make a small amount of approximately O.IM solution of this salt. Place equal volumes of this solution and of 0.05M ferric sulfate solution in two test tubes side by side. Both solutions contain the same concentration of iron. Add the same amount of potassium thiocyanate solution to each. Repeat with 0.05M ferric ammonium sulfate. Note the colors before and after adding thiocyanate, and explain. 

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