Silica (SiO2) participates in some interesting reactions with water:
SiO2(s) + 2H20(l) <-> H4SiO4(aq) ; Keq= 2.0 x 10^-3 M
H4SiO4(aq) <-> H3SiO4-(aq) + H+(aq) ; pKa=9.46
(a) What is value of [H4SiO4(aq)]?
(b) Knowing the pH and the value of [H4SiO4(aq)], what is the value of [H3SiO4-(aq)] when the pH=7.0? and when pH=10.0?
(c) The total solubility of silica is the sum of [H4SiO4(aq)] and [H3SiO4-(aq)]. Calculate the total solubility both when the pH=7.00 and when the pH=10.0
Does the way the solubility depends on acidity makes sense?