Suppose a student titrates a 10.00-mL aliquot of saturated Ca(OH)2 solution to the equivalence point with 13.65 mL of 0.0234 M HCl.

What was the initial [OH − ]?
What is the experimental value of Ksp?

1 answer

First calc. the moles from M and L: (.0234)(.01365)= 3.19e-4

Determine moles Ca(OH)2 titrated:

(3.19e-4)/2 = 1.60e-4 mol

Remember, every one Ca(OH)2 titrated requires 2 H+

[Ca2+] = (1.60e-4)/.01 = .01597M
[OH-] = (.01597)(2) = .0319 M

Ksp = (.01597)(.0319)^2 = 1.63e-5