- Cryolite In Cryolite Sodium Hexafluoroaluminate The Six Fluoride Ions Are Bound With Decreasing Strength The Consecut 1 (25.92 KiB) Viewed 54 times
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Cryolite In Cryolite (sodium hexafluoroaluminate) the six fluoride ions are bound with decreasing strength. The consecutive constants, given as log K, are respectively 6.13, 5.02, 3.85, 2.74, X. 0.47, for n=1,2,3,4,5,6, respectively) 11) (6) Give the chemical formula and structure of sodium hexafluoroaluminate. 12) (9) Give estimates of lower and upper limits for log Ks = X using other given log K values (log Ke and log Ka) The K-constants were determined from a pH-measurement Ks was determined from the following single experiment and by knowledge of the other constants A solition including aluminum nitrate (c(AP)=1.00-10-³M), nitric acid (c(H+) = 9:10 10-M), potassium fluoride (c(F-) = 28.62 10-³M) was used. The pH of this solution was measured to 321 pka for hydrofluoric acid was measured in a corresponding solution to 294 13) (12) Calculate log Ks (Hint i) Account for protons and find the protonated- and the free fluoride actual concentrations ([HF]and [F] in unit M), i) determine the average ligand number and in) use the most simple approximation to determine log Ks, and iv) make a correction to log K's accounting for the first determined log K's being at least too small or too big