Answer to Question #178420 in General Chemistry for gj,

Question

Calcium hydroxide is only slightly soluble in water. The K_sp value of Ca(OH)₂ is 1.3 x 10^-6.

(a) Write the equation for the dissociation of calcium hydroxide in water and the solubility product constant (K_sp) expression for calcium hydroxide. 

(b) Calculate the solubility of calcium hydroxide.

(c) How would the solubility of calcium hydroxide vary (more soluble, less soluble, or the same) if the salt were to be dissolved in a 0.10 M solution of calcium chloride (CaCl₂) rather than pure water? Justify. 

(d) Would precipitation of calcium hydroxide be expected if a 0.25 L sample of 0.100 M NaOH is mixed with 0.50 L of 0.300 M CaCl₂? Justify with a calculation. 

Answer 1

a)

Ksp = [Ca2+][OH-]2

b) 3.19M

c)By changing the pH of the solution, you can change the charge state of the solute. If the pH of the solution is such that a particular molecule carries no net electric charge, the solute often has minimal solubility and precipitates out of the solution.

d) No, a precipitate forms when a solute doesn't completely dissolve in a Solvent.