posted by Suha on .
Calculate the Ksp Ca(OH)2 25cm3 of a saturated solution required 11.45cm3 of 0.1mol/dm3 HCl for neutralization.
2HCl + Ca(OH)2 --> CaCl2 + 2H2O
1 dm^3 = 1L
moles HCl used = M x L.
Look at the coefficients in the balanced equation. That many moles HCl means 1/2 that for moles Ca(OH)2.
That is the # moles Ca(OH)2 in 25 cc. Convert that to moles in 1 dm^3 (1L) solution. Let's call that S for solubility. Then
Ca(OH)2 ==> Ca^+2 + 2OH^-
Substitute the value of S (or 2S) into the Ksp expression and solve for Ksp. Post your work if you get stuck.
Ksp = (Ca^+2)(OH^-)^2