# What is the minimum concentration of iodide ion

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48. What is the minimum concentration of iodide ion required to limit the concentration of lead ion in solution to a maximum of 1.0 10 6 M? K sp for PbI 2 is 8.7 10 9 . a. 1.7 10 2 b. 1.8 10 1 c. 7.6 10 5 d. 8.7 10 3 e. 9.3 10 2 ANS: E OBJ: Calculate the minimum ion concentration required to achieve the stated concentration of a counter ion with which it can form an insoluble compound. M M M M M TOP: Uses of Solubility Product Constants
49. An aqueous solution of silver bromide is adjusted so that the concentration of silver ion in solution is limited to a maximum of 1.0 10 9 M . Which of the following statements about the solution is false K sp for AgBr is 3.3 10 13 ? . . . OBJ: Identify the incorrect description of a solid-solution equilibrium.
TOP: Uses of Solubility Product Constants
50. Which of the following responses contains all of the true statements? I. An ion may never be completely precipitated from solution, even when the precipitating reagent is used in large excess. II. If solid NaCl is added slowly to a saturated solution of NiS in contact with solid NiS, nothing significant will happen to the NiS. III. Consider two relatively insoluble 1:1 salts (i.e., one cation and one anion per formula unit) containing the same cation, whose solubility products differ by 10 4 . More than 90% of one anion can be precipitated before the other precipitates when the common cation is added to a solution of the two anions.
ANS: E OBJ: Identify the correct descriptions of solid-solution equilibria. TOP: Fractional Precipitation 51. A solution is 0.012 M in Pb(NO 3 ) 2 and 0.20 M in Sr(NO 3 ) 2 . Solid Na 2 SO 4 is added until a precipitate just begins to form. The precipitate is ____ and the concentration of sulfate ion at this point is ____. K sp for PbSO 4 is 1.8 10 8 and for SrSO 4 is 2.8 10 7 . M M M M M
Whitten 10e Test Bank 13 TOP: Fractional Precipitation