Mercury potassium iodide

The photometric determination using Nessler s reagent (alkaline solution of a complex mercury-potassium iodide K2[Hgl4]) is based on ... 

Mercury potassium iodide, potassium mercuriiodide, potassium iodohydrargyrate. 

Mercaptans and Mixtures, liquid. 1228 28 Mercury Potassium Iodide 1643 53... 

Acetamido-4-methylselenazole can react with mercuric acetate to yield 5-mercuriacetate derivatives that can be converted to the chloro derivatives by the action of sodium chloride. Treatment with potassium iodide leads to reduction regenerating the initial compound with loss of mercury (Scheme 16) (4). 

Industrial Hquid chlorine is routinely analy2ed for moisture, chlorine, other gaseous components, NCl, and mercury foUowing estabHshed procedures (10,79). Moisture and residue content in Hquid chlorine is determined by evaporation at 20°C foUowed by gravimetric measurement of the residue. Eree chlorine levels are estimated quantitatively by thiosulfate titration of iodine Hberated from addition of excess acidified potassium iodide to the gas mixture. 

Titanium diiodide may be prepared by direct combination of the elements, the reaction mixture being heated to 440°C to remove the tri- and tetraiodides (145). It can also be made by either reaction of soHd potassium iodide with titanium tetrachloride or reduction of Til with silver or mercury. 

It is therefore possible to determine cations such as Ca2+, Mg2+, Pb2+, and Mn2+ in the presence of the above-mentioned metals by masking with an excess of potassium or sodium cyanide. A small amount of iron may be masked by cyanide if it is first reduced to the iron(II) state by the addition of ascorbic acid. Titanium(IV), iron(III), and aluminium can be masked with triethanolamine mercury with iodide ions and aluminium, iron(III), titanium(lV), and tin(II) with ammonium fluoride (the cations of the alkaline-earth metals yield slightly soluble fluorides). 

Calculate the concentration of the mercury(II) nitrate solution from the known concentration of the potassium iodide solution. 

Discussion. J. Nessler in 1856 first proposed an alkaline solution of mercury(II) iodide in potassium iodide as a reagent for the colorimetric determination of ammonia. Various modifications of the reagent have since been made. When Nessler s reagent is added to a dilute ammonium salt solution, the liberated ammonia reacts with the reagent fairly rapidly but not instantaneously to form an orange-brown product, which remains in colloidal solution, but flocculates on long standing. The colorimetric comparison must be made before flocculation occurs. 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

Red phosphorus, sulfur but with carbon, the observed ignition has been attributed to presence of impurities mercury iodide, potassium iodide, silver nitrate, potassium carbonate. 

Fluorine decomposes calcium iodide, lead iodide, mercury iodide and potassium iodide at ambient temperature, and the liberated iodine ignites, evolving much heat. 

On shaking sulfenyl chlorides with mercury or a solution of potassium iodide, disulfanes are produced ... 

Mercury(II) iodide is precipitated in its yellow form by adding a stoichiometric amount of potassium iodide to an aqueous solution of mercury(II) salt (e.g., HgCb) ... 

In caustic soda or caustic potash solution, mercury(TI) iodide forms complex salts, Na2Hgl4 and K2Hgl4, respectively. Alkaline solution of this complex in excess potassium hydroxide is known as Nessler s reagent, used to analyze ammonia. The reaction of Nessler s reagent with ammonia may be written as ... 

Mercury(I) nitrate undergoes double decomposition reactions with anions in aqueous solution, forming corresponding mercury(l) salts. With potassium iodide and sodium bromide, yellow mercury(l) iodide and white mercury(I) bromide precipitate, respectively. Similarly, mercury(l) nitrate in acid medium reacts with dilute sulfuric acid to form mercury(1) sulfate ... 

Mercury(II) oxide reacts with potassium iodide in solution, forming potassium tetraiodomercurate(II) ... 

In many cases such as at water-mercury interfeices electrolytes are positively adsorbed. The application of the kinetic theory to surface films of molecules leads, as we have seen, to a ready interpretation of the lowering of the surface tension by capillary active nonelectrolytes. For electrolytes an additional fiictor has to be considered, namely the mutual interaction of the electrically charged ions adsorbed. As we shall have occasion to note the distribution of the adsorbed ions, both positive and negative, at an interface such as water-mercury is not readily determined, but it is clear from a consideration of the data of Gouy that mutual ionic electrical repulsion in the interface is an important factor. In the case of potassium iodide, for example, for very small values of F the Traube relationship... 

Only a little 3,5-di- and penta-iodopyridine is obtained when pyridine reacts with iodine in the vapour phase. Treatment of pyridine with iodine in 50% oleum furnishes 3-iodo-(18%) and some 3,5-di-iodo-pyridine. This is probably the result of electrophilic substitution by I+, with oleum performing in the role already discussed (57JCS387). The products of iodination of quinoline are not well defined however, a reviewer (77HC(32-1)319) has pointed out that one such product (formed by heating quinoline with iodine and potassium iodide at 160-170 °C in the presence of mercury(II) chloride) has a melting point identical with that of 3-iodoquinoline. 

The compound Ru3H(CO)9(C2-t-Bu) (1.243 g, 1.950 mmol) is treated with alcoholic potassium hydroxide (17.5mL of 0.128 M, 2.24 mmol) followed by mercury(II) iodide (0.444 g, 0.978 mmol) as outlined in the procedure in Section (B.l). The resulting solution is allowed to stir under a carbon monoxide atmosphere until a bright yellow precipitate forms. The reaction time is typically 30 to 45 min. Upon precipitation, the reaction mixture is evaporated to dryness under reduced pressure. The resulting residue is washed first with 50 mL of absolute ethanol and then with 25 mL of dichloromethane. The remaining yellow residue is recrystallized from hot THF. Yield 1.16-1.20 [81-84% yield based on Ru3H(CO)9(C2-t-Bu)]. 

Reaction to Ammonium Ion (Nessler s Reagent). Introduce 5 ml of a 0.1 N mercury(II) nitrate solution heated to 80 °C into a 50-ml beaker and add 5 ml of a 0.1 A potassium iodide solution. Cool the mixture, let the precipitate settle, pour off the solution, and wash the precipitate three times with cold water by decantation. Add 0.2 g of potassium iodide dissolved in 5 ml of water to the precipitate. When the latter dissolves, pour in 3 ml of a 10% sodium hydroxide solution and transfer the contents into a dark jar. 

Preparation of Mercury(II) Iodide. Prepare a 0.02 N solution of mercury(II) nitrate. Boil 2-3 ml of the solution, add an equal volume of a 0.02 N potassium iodide solution, and let the mixture stand to your next lesson. Filter off the precipitate (what is its composition ) through a paper filter, wash it with water, and dry it in a drying cabinet at 70 °C. What happens to the salt when it is kept in the air ... 

Mercury fulminate also dissolves in many solutions of various salts, but in some of them (e.g. potassium iodide, sodium thiosulphate) it undergoes rapid decomposition. 

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