Precipitation silver chloride

Iron(III) nitrate is soluble, but silver chloride is not When these two solutions are mixed, silver chloride precipitates. 

The negative voltage shows that the state of equilibrium favors the reactants more than the products for the reaction as written. For standard conditions, the reaction will not tend to occur spontaneously. However, if we place Ag(s) in 1 M H+, the Ag+ concentration is not 1 M— it is zero. By Le Chatelier s Principle, this increases the tendency to form products, in opposition to our prediction of no reaction. Some silver will dissolve, though only a minute amount because silver metal releases electrons so reluctantly compared with H2. It is such a small amount, in fact, that no silver chloride precipitate forms, even though silver chloride has a very low solubility. 

A complete ionic equation for a precipitation reaction shows all the dissolved ions explicitly. For example, the complete ionic equation for the silver chloride precipitation reaction shown in Fig. 1.5 is... 

FIGURE 1.5 (a) Silver chloride precipitates immediately when sodium chloride solution is added to a solution of silver nitrate, (b) If we imagine the removal of the spectator ions from the complete ionic reaction (top), we can focus on the essential process, the net ionic reaction (bottom). 

FIGURE 11.22 When ammonia is added to a silver chloride precipitate, the precipitate dissolves. However, when ammonia is added to a precipitate of mercury(l) chloride, mercury metal and mercury(ll) ions are formed in a redox reaction and the mass turns gray. Left to right silver chloride in water, silver chloride in aqueous ammonia, mercury(l) chloride in water, and mercury(l) chloride in aqueous ammonia. 

For the filtration use a small filter tube with a fritted glass filter (cf. Fig. 41). Pour into the filter a suspension of finest asbestos (for Gooch crucibles) to form a layer 2-3 mm. thick after sucking dry at the pump. Before using the filter tube, pour in a little silver chloride precipitated in the cold. As soon as the filtrate is clear the tube is ready for use. 

Caustic washing and thermal treatment of silver chloride precipitate are performed to achieve a 5X decontamination level for shipment to an offsite silver recovery operation. 

Will silver chloride precipitate under the given conditions ... 

Thionyl chloride nitrate and thionyl nitrate are prepared in situ from the reaction of a solution of thionyl chloride in THF with one and two equivalents of silver nitrate respectively, during which time silver chloride precipitates from solution. ... 

The reduction of silver chloride, precipitated in the presence of excess chloride ion, yielded the S-shaped curve typical of an autocatalyzed reaction (James, 25). The initial reaction rate, measured in terms of the reciprocal of the time required to complete 5 % of the total reaction, varied directly as the hydroxylamine concentration and inversely as the chloride ion concentration when the latter was relatively large. The specific surface of the freshly prepared precipitate, as measured by dye adsorption, decreased with aging, and the reaction rate decreased proportionately. 

The pH dependence of the rate of development by hydroxylamine indicates that the monovalent ion is the active species. The rate varies as about the 0.65 power of the hydroxylamine concentration at pH 12.7 and the 0.75 power at pH 10.8. These results suggest adsorption of the hydroxylamine ion, and are in complete agreement with previous findings for the catalyzed reduction of silver chloride precipitates. 

The correlation between the number of ammonia molecules present and the number of equivalents of silver chloride precipitated led Werner to the following... 

Salts therefore, are prepared (1) from solutions of acids and bases by neutralization and separation by evaporation and crystallization (2) from solutions of two salts by precipitation where the solubility of the salt formed is slight (e.g., silver nitrate solution plus sodium chloride solution yields silver chloride precipitate [almost all as sulid], and sodium nitrate present in solution as sodium cations and nitrate anions [recoverable as sodium nitrate, solid by separation of silver chlondc and subsequent evaporation of the solution]) (3) from fusion of a basic oxide (or its suitable compound—sodium carbonate above) and an acidic oxide (or its suitable compound—ammonium phosphate), since ammonium and hydroxyl are volatilized as ammonia and water. Thus, sodium ammonium hydrogen phosphate... 

FIGURE 1.6 Silver chloride precipitates immediately when silver nitrate solution is added to a solution of sodium chloride. 

The concentration of Cl- ions can be measured gravimetrically by precipitating silver chloride, with silver nitrate as the precipitating reagent in the presence of dilute nitric acid. The white precipitate is filtered off and its mass is determined, (a) Calculate the Cl ion concentration in 25.00 mL of a solution that gave a silver chloride precipitate of mass 3.050 g. (b) Why is the method inappropriate for measuring the concentration of fluoride ions ... 

The mercury substances are filtered, and silver ions (Ag+) are detected in the filtrate by adding hydrochloric acid (HC1), which releases the silver ions from the silver-ammonia-complex ion [Ag(NH3) 2+], allowing the silver ions to combine with chloride ions (Cl") to form silver chloride precipitate (AgCl) ... 

The exchange of silver ion between a precipitate of silver chloride and a solution of silver nitrate reaches isotopic equilibrium very rapidly (152). Because of the low solubility of silver chloride, a favorable ratio exists at equilibrium between the silver atoms in the precipitate and in the solution. For this reason, If a silver chloride precipitate is added to a solution containing only- trace amounts of radioactive silver, a high percentage of this radioactive silver will have exchanged with the silver in the precipitate by the time equilibrium is attained. 

SOLUBILITY PRODUCT The saturated solution of a salt, which contains also an excess of the undissolved substance, is an equilibrium system to which the law of mass action can be applied. If, for example, silver chloride precipitate is in equilibrium with its saturated solution, the following equilibrium is established ... 

This expression shows that under equilibrium conditions the concentration of chromate ions in the solution is always much greater than that of the chloride ions. If therefore to a mixture of chloride and chromate ions, silver ions are added, these will combine with chloride ions, forming silver chloride precipitate until the concentration of chloride ions in the solution decreases to such an extent, that the ratio expressed in equation (iii) is achieved. From then onwards the two precipitates will be formed simultaneously. If a 01m solution of sodium chloride is titrated with silver nitrate in the presence of 0 002m potassium chromate, the concentration of chloride ions at which silver chromate starts to precipitate can be expressed from equation (iii) ... 

Sunlight or ultraviolet irradiation decomposes the silver chloride precipitate, which turns to greyish or black owing to the formation of silver metal ... 

If the silver chloride precipitate is filtered off, washed with distilled water, and then shaken with sodium arsenite solution it is converted into yellow silver arsenite (distinction from silver bromide and silver iodide, which are unaffected by this treatment). This may be used as a confirmatory test for a chloride. 

A 300-mg (0.40mmol) quantity of Ira s-[PtHCl(PPh3)2]. is placed in a 25-mL Schlenk flask and dissolved in 8 mL of dichloromethane and 2 mL of methanol. The solution is cooled to — 20 °C, and 105 mg (0.40 mmol) of silver trifluoromethanesulfonate is added to the stirred solution. The silver chloride precipitate is removed by Altering, and the solution is taken to dryness under... 

Suppose a small amount of NaCl(s) is added to a saturated solution of AgCl. What happens Sodinm chloride is qnite solnble in water and dissolves to form Na (rjq) and Cl (aq) ions, raising the concentration of chloride ion. The quantity Qo = [Ag ][Cl ] then exceeds the K p of silver chloride, and silver chloride precipitates until the concentrations of Ag (aq) and Cl (aq) are snfficiently reduced that the solubility product expression once again is satisfied. 

Silver chloride precipitates. Other chlorates give mixtures of the glycol and the chlorohydrin. 

---