Question

The solubility product constant for Ba(IO₃)₂ is 1.57×10^-9 at 25 ^oC. What is the molar concentration of IO₃^- ions in a saturated solution of Ba(IO₃)₂? Assume an ideal solution at 25 ^oC.

How many grams of Ba(IO₃)₂ (487.1 g/mol) can be dissolved in 1000 mL of pure water at 25 ^oC?

How many grams of Ba(IO₃)₂ can be dissolved in 1000 mL of a 0.100 M KIO₃ solution at 25  ^oC? Use activities for this calculation.

Answer 1

c) When we consider the solubility of Ba(IO) in KIO solution, we need to include activity coefficients in our calculation. In very dilute solution, activity is equal to molar concentration For a species A, activity a = [A] YA where [^) = molar conc. Of A VA = activity Coefficient 0.775 Ba (19), (5,= Barton + 2 Ig can Ksp = a (Bart). (a Iq}, where acBaht) = activity of Ba²+ a Best = [Balt] Yeat ; ato = [9 11193 039; YIO **** Let 's'be the molar solubility of Balto) in 0.100M KI a To = [[91219) from KIC - = 0.100) 0.775) = 0·0775 Bal+ = Sx0.38 ; a tó = 250.775 = 1.555. Baltg) ² Ba²+ + 2 Ig (0.38 1.55'8' + 0.0775) 1.55(s) + 0.0775 0.0775 as s is too small. Ksp = 1.57 x10º = 0.38 (S *@.0775)2 = 2.282 *10*xs s = 1:57x10_ 0.6879 x106 2.282 x 103 6.88 x107 m. Mass of Baco) - 6-88 x 67 moles x 487.18/mol - 3.35x10 '9. = 3.35 xio g. to Is this correct ? -4