Consider the weathering reaction describing the breakdown of K-feldpar to form the clay mineral kaolinite, a reaction of particular importance in tropical soils:
KAlSi3O8 + H++ 4.5 H2O(l) ? 0.5 Al2Si2O5(OH)4 + K+ + 2(H4SiO^0)4(aq
(B) Calculate the value of the equilibrium constant