The solubility of the mineral otavite (CdCO3) is defined by the following reaction: Cd 2+ + CO3 2- = CdCO3 ; logK = -12.01
A) Dissolved Cd 2+ readily complexes with aqueous chloride (Cl - ) anions to form dissolved Cd-chloride complexes, according to:
Cd 2+ + Cl - = CdCl + ; logK = 1.98
Cd 2+ + 2Cl - = CdCl2 0 ; logK = 2.60
Calculate the total concentration of dissolved cadmium (i.e. sum of the concentrations of free Cd 2+ and Cd-chloride complexes) in a 0.1M NaCl solution that is in equilibrium with otavite at atmospheric PCO2 and a pH of 8.5. To what extent does chloride increase the solubility of otavite? Note: for questions 5a and b assume that concentration = activity for all species, and assume that aqueous Cd 2+ forms aqueous complexes with chloride only.