For the sparingly soluble salt AgCl, the solubility product expression is
- A. Ksp = [Ag+] + [Cl-]
- B. Ksp = [AgCl] divided by [Ag+][Cl-]
- C. Ksp = [Ag+][Cl-] divided by [AgCl]
- D. Ksp = [Ag+][Cl-]
Explanation
Silver chloride dissociates into one silver ion and one chloride ion, so Ksp is simply the product of the two concentrations, and the solid does not appear because its concentration does not vary. If the solubility is s moles per cubic decimetre then both ion concentrations equal s and Ksp equals s squared. Concentrations are always multiplied in such expressions, never added.