Respuesta :

CaF₂ ↔ Ca²⁺ + 2 F⁻
Solubility product Ksp is the product of ions forming a sparingly soluble salt each ion raised to power equal its stoichiometric factor in balanaced equation.
So:
Ksp CaF₂ = [Ca²⁺] [F⁻]²
                = (0.1) (0.02)² = 4.0 x 10⁻⁵