What is the maximum concentration of Ni²⁺ that can be added to a 0.00500 M solution of Na₂CO₃ before a precipitate will form? (Ksp for NiCO₃ is 1.30 × 10⁻⁷)

Answer 1

"To be, or not to be, that is the question."

To precipitate or not to precipitate, that is the Q.

As long as Q < K (in this case Ksp), a precipitate NiCO₃ will not form; until Q=K, a precipitate forms.

Qsp (not an authorized term) = [Ni²⁺][CO₃ ^2-] = [Ni²⁺] x 0.00500 (M) =Ksp = 1.30 × 10⁻⁷

Max [Ni²⁺] = 1.30 × 10⁻⁷ / 0.00500 = 2.60 × 10⁻⁵ M before NiCO₃ forms.