Solubility product of AgBr

Silver(I) forms a dithiosulfato complex for which /32 = 2 x 10 in dilute aqueous solution at 25 °C. Given that the solubility product of AgBr is 5.3 x 10 (and assuming that ionic strength effects are negligible), show that the minimal total concentration of Na2S203 needed to dissolve 1.00 g silver bromide in 1.00 L of water at 25 °C is 0.0123 mol L . Note that Na+ is introduced simply as the counterion of 8203 and does not enter into the calculations. 

From the following information, calculate the solubility product of AgBr ... 

A familiar example is the reaction of dilute ammonium hydroxide with silver ions to give Ag(NH3)2+, which reduces the concentration of free Ag+ to a value below that needed to exceed the solubility product of AgCl (but not that of AgBr or Agl). If ammonia is replaced by cyanide ions, which form more stable complexes, only the more insoluble Agl can be precipitated. Hence by choice of the masking agent used a cation can be selectively masked towards some reagents but not others. 

AgBr will be bromide selective, and so on. The selectivity observed with such silver halide precipitates follows exactly the solubility product of the respective silver salt. Consequently, the following sequence is always observed for any given silver precipitate membrane ... 

Then we determine the value of the ion product for AgBr and compare it to the solubility product constant value. 

For a 1 1 electrolyte such as AgBr, the solubility product is directly related to the solubility of the ions ... 

The extraordinarily high sensitivity of radiochemical methods makes it possible to measure solubility equilibria of sparingly soluble compounds or distribution equilibria in the range of very low concentrations. This is illustrated for the silver halides AgCl, AgBr and Agl in Fig. 18.1, in which the concentration of Ag in solution is plotted as a function of the concentration of the corresponding halides NaCl, NaBr and Nal. The fall in the curves is due to the solubility product, and the rise is due to complex formation. The minima of the curves, which cannot be found by electrochemical methods, are given by the solubility of the undissociated species. 

Calculate the simultaneous solubility of AgSCN and AgBr. The solubility products for these two... 

Because the solubility products Ks0 for Agl, AgBr, and AgCl are sufficiently different, it is possible to titrate a mixture of halides with silver,... 

The analysis of solubility curves and precipitation boundaries is illustrated for the precipitation of silver bromide (mixing aqeuous solutions of KBr and AgN03) in Figure 8.8 (Fiiredi, 1967). The curves are approximated by tangents and the values of the slopes, b, of the various parts of the curve determine the compositions of the complexes. For example, slope b =— for this 1 — 1 electrolyte represents the solubility product and slope Z = 0 represents the complex AgBr (aq). The other portions of the curve represent the compositions of the other complexes AgBr and Ag Br " + where the slope... 

When 1,3,5-cycloheptatriene reacts with one molar equivalent of bromine at 0°C, it undergoes 1,6 addition, (a) Write the structure of this product, (b) On heating, this 1,6-addition product loses HBr readily to form a compound with the molecular formula CyHyBr, called tropylium bromide. Tropylium bromide is insoluble in nonpolar solvents but is soluble in water it has an unexpectedly high melting point (mp 203 °C), and when treated with silver nitrate, an aqueous solution of tropylium bromide gives a precipitate of AgBr. What do these experimental results surest about the bonding in tropylium bromide ... 

Using electrochemical data, what is the solubility product constant, of AgBr... 

With such a cell it is possible in a single titration to determine the concentrations of iodide, bromide, and chloride ions in solution, since the different solubility products are reflected in three distinct steps in the electrode potential (or e.m.f. of the cell), corresponding to the complete precipitation of Agl, AgBr and AgCl (figure P.9). 

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