given the solubility product;Ksp,of calcium hydroxide is 0.0000064M,caculate its solubility at this temperature in
i.water
ii.0.1M calciumchloride solution
To calculate the solubility of calcium hydroxide (Ca(OH)2) in water and in a 0.1M calcium chloride (CaCl2) solution, we need to use the solubility product constant (Ksp) and the stoichiometry of the dissolution reaction.
The balanced equation for the dissolution of calcium hydroxide is:
Ca(OH)2(s) ⇌ Ca2+(aq) + 2OH-(aq)
The Ksp expression for calcium hydroxide is:
Ksp = [Ca2+][OH-]^2
Now let's calculate the solubility in each case:
i. Solubility in water (pure solvent):
In this case, we assume that there are no other ions present in the solution except for the ions that come from the dissolution of calcium hydroxide.
Let's assume the solubility of calcium hydroxide is "s" moles per liter.
From the balanced equation, we know that the concentration of Ca2+ is also "s" moles per liter and the concentration of OH- is "2s" moles per liter.
Substituting these values into the Ksp expression, we have:
Ksp = [Ca2+][OH-]^2
0.0000064 = s * (2s)^2
0.0000064 = 4s^3
Now solve for s:
s^3 = 0.0000064 / 4
s^3 = 0.0000016
s ≈ 0.01 M
Therefore, the solubility of calcium hydroxide in water is approximately 0.01 M.
ii. Solubility in 0.1M calcium chloride solution:
In this case, the presence of additional calcium ions from the calcium chloride solution will affect the solubility of calcium hydroxide.
Let's assume the additional calcium ions from the calcium chloride solution react with OH- ions, reducing their concentration by "x" moles per liter.
Thus, the concentration of OH- becomes "2s - x" moles per liter.
The concentration of Ca2+ remains as "s" moles per liter.
The concentration of calcium ions from the calcium chloride solution is 0.1M.
Now we substitute these values into the Ksp expression:
Ksp = [Ca2+][OH-]^2
0.0000064 = s * (2s - x)^2
Since the concentration of calcium ions from the calcium chloride solution is 0.1M, the concentration of Ca2+ is now "s + 0.1" moles per liter.
Ksp = (s + 0.1) * (2s - x)^2
Solving for x can be quite complex, so we'll need additional information to determine the actual solubility.
In summary, the solubility of calcium hydroxide in water is approximately 0.01 M, but to calculate the solubility in the presence of a 0.1 M calcium chloride solution, we need additional information about the values of s and x.