Question

find the concentration of Ag+ (silver ion) and CO3 2- (carbonate ion) in a saturated silver carbonate solution with 0.01 M of KNO3 (potassium nitrate). The equilibrium constant for silver carbonate is 8.1 X 10 -12 .

Answer 1

Ag₂CO_3(s] ⇌ 2Ag⁺_(aq] + CO₃^2-_(aq]

By definition, the solubility product constant will be

Ksp=[Ag⁺]²⋅[CO₃^2-]

This dissociation is an equilibrium reaction between the undissolved solid and its dissolved ions at equilibrium in accordance to the value of the solubility product constant.

The equilibrium reactions are governed by Le Chatelier's Principle, which states that when a system experiences a disturbance (such as concentration, temperature, or pressure changes), the position of equilibrium shifts to counteract the change to reestablish a new equilibrium state.

For Ag₂CO₃ , let CO₃^2- = x, then Ag+ = 2x

Ksp = 8.1 x 10^-12 = [Ag⁺] 2[CO₃^2-] = (2x)²x = 4x³

Therefore, x = [CO₃^2-] = 1.3 x 10^-4 M

Hence [Ag⁺] = 2.5 x 10^-4 M