Question

6.(12pts) Should a precipitation of Pb(IOs)2(s) form when 55.0 ml of 0.0450 M Pb(NO:)2 (aq) solution is added to 48.0 ml of 0.215 M NalOs(ag) solution? Assume that at the temperature at which the experiment is performed, Ks of Pb(IOs)2(s) is 2.8 x 10-13 All work must be shown- a guess is not sufficient Calculate the solubility of Cr(OH)s in grams per liter in a system buffered at pH 10.6. Data:Kn of Cr(OH)3(s) = 6.3 x 10-31 . The molar mass ofCr(OH)3(s) = 103.02. Krof Cr(OH)-(g)-8.0 x 1029 Hints: (a) 2pts Write theKsp equilibrium reaction for Cr(OH)s(s) 7. (10pts) (b)2ptswritek expression for the reaction Cr"(aq) + 4 OH(ag)?Cron-(aa) 2 pts Add the equations in (a) and (b) to get the overall equation. Also use the Ksp and Kr to get a Kaxerall for the overall reaction. (c) (d) 4 pts Set up a standard equilibrium ICE table involving the overall reaction and determine the desired solubility (in g/L)

Answer 1

- molai Tolal voluma Total volume 2-087 м o3 mL I-90.3 Hou Qe is jreater then ksp So preipitedion will takes plau e dor

3 Ans Cv з+ + 4 0 Hー→ Су@1-j), → (2) as it is in sol Co H 6.3x10-31 x 8x1089 -3.4 3.98 xo

OH 1.3 x lo-"J ( 3.98x10" 4 -I 6 81.9 6 x lo Sp 8.196 x lo 5