Question

Determine the activity of the metal ion species in each of the following saturated solutions. A. CaF2 (Ksp = 3.2 X 10-11) in pure water B. CaF2 buffered at ionic strength 0.100 M C. Ag3PO4 (Ksp = 2.8 X 10-18) in pure water D. Ag3PO, buffered at ionic strength 0.050 M

Answer 1

Cafe & Ca 2+ + 25 s- solubility het to s tot o s 25 solubility Product Product of conc. of dissolved product each raised to power to its Ksp = 5 x(25) 2 stochiometic coefficient ksp = 253 3. 2x10-11 = S3 - a 3/ 0.8 10-11 as 0.8810-11 58 x 10-12 -5 = 2x104 activity is defined as effletive one. = dissolved amount - s = 2x10-4 mol/L

Am I 1 I calzi") Cafe ? ca't + 28- 010 / ( (*). 4 + 2x (12²) 0.1 = (4 + 2 x oil = 3x 1 0.033 malf=2 f activity Au Aga poy - 3Ag+ + Poy 3- o 35 s Ksp = (38 93 x 5 2.8x10-18 = 27 54 100 x 0. 1037 X10 18 = 5 100 al 10.37 X1020 S = 1.7945 x 10 most unit may

Hu Aga poy sagt + Po. I = { azi - k l 32 (1)2 + x (-3) 2) oos = (3x + 9x) 0.05 = 6x. 0.00833 M = x. 2 activity