At some other temperature, a solid sample of Ca(OH)2 is shaken with 0.0100 M CaCl2.

Question

Once equilibrated, some solid Ca(OH)2 remains undissolved.
The solution is filtered and a 20.00 mL sample requires 38.80 mL of 0.0100 M HCl to neutralize it.
Calculate the value for Ksp of Ca(OH)2 from this data

Answer 1

Ca(OH)2 ==> Ca^2+ + 2OH^-

Ksp = (Ca^2+)(OH^-)^2
(Ca^2+) = 0.01M from the CaCl2.
(OH^-) = from the HCl data.
mols HCl = M x L = 0.01M x 0.03880L = ?
(OH^-) = 1/2 x that since there are two H^+ required for the Ca(OH)2