What is the molar solubility of LaF3 in water? The Ksp for LaF3 is 2 x 10-19. Report your answer in scientific notation with two significant figures

Answer 1

Ksp = [La³⁺] [F^1-]³

Since LaF3 ====> La³⁺ + 3F^1-, [F^1-] = 3 x [La³⁺], so the first equation can be written

Ksp = [La³⁺] [3La³⁺]³ = [La³⁺] x 27 x [La³⁺]³ = 27 x [La³⁺]⁴ Now solve for [La³⁺]

[La³⁺] = (Ksp / 27) ^1/4 (find the fourth root of (Ksp / 27))

[La³⁺] = (2 x 10^-19 / 27)^1/4 = 9.3 x 10^-6 M = [LaF₃] The concentration of La³⁺ is equal to the concentration of LaF₃.

check the math.