In calculating the molar solubility of silver carbonate in a solution of 0.125 M sodium carbonate (knowing the Ksp=8.46×10−12) I have a question with the solution provided which is as follows:
Ksp=[AgX+]2[COX3X2−], the initial concentration of COX3X2− is 0.125 M. Let x denote the change in concentration for AgX+.
Therefore Ksp=x2(12x+0.125). Assuming the change for COX3X2− is negligible, that gives Ksp=x2⋅(0.125), which substituting the Ksp value gives x≈8.227×10−6, which is the molar solubility.
What I'm confused about is shouldn't the molar solubility be half that number since AgX2COX3−⇀↽−2AgX++COX3X2−, meaning that for each mole that AgX+ increases, AgX2COX3 only decreases by half that amount? Could someone just explain whether my reasoning is correct or not?
