Question

A precipitate could form when you mix Ca⁺²and F^-1? What is the value of Qsp for the precipitate solubility when 0.275 L of 0.30M Ca²⁺ is mixed with 0.204 L of 0.060 M F^-1?

**Remeber Volumes are additive since it is a mixture

Answer 1

Answer

i) A precipitate could form

ii) Qsp = 1.13×10^-4

Explanation

Solubility equillibrium of CaF2 is

CaF2(s) <------> Ca²⁺(aq) + 2F^-(aq)

Ksp = [Ca²⁺] [F^-]² = 3.9 ×10^-11

^{​​​​​​}Concentration after mixing

[Ca²⁺] = 0.30M / (0.479L/0.275L ) = 0.1722M

[F^-] = 0.060M/(0.479L/0.204L) = 0.0256M

Qsp = [Ca²⁺][F^-]²

Qap = 0.17222 × (0.0256)²

Qsp = 1.13×10^-4

^{Qsp > Ksp}

^Therefore,

Precipitate will form