Class: Ksp of Calcium Hydroxide Be sure to show your work for any calculations 1
ID: 1012838 • Letter: C
Question
Class: Ksp of Calcium Hydroxide Be sure to show your work for any calculations 1. Complete the reaction for the synthesis of Ca(oH)z: CaCl2 (aq) NaoH (aq) When 25.00 mL of saturated Ca(oH), is titrated with a o.024 M solution of HCI, 35.45 mL of HCI is needed to reach the equivalence point of the above reaction. What is the concentration of Ca (OH)2? 3. A saturated solution has a concentration of Ca(OH)2 equal to 0.014 M. Calculate the value of Ksp. 4. Check at least two sources to find the value of Ksp of Ca(oH)2Give your sources.Explanation / Answer
1)
the reaction is given by
CaCl2 + 2NaOH ---> Ca(OH)2 + 2 NaCl
2)
the reaction is given by
Ca(OH)2 + 2 HCl ---> CaCl2 + 2H20
we can see that
moles of HCl required = 2 x moles of Ca(OH)2 present
now
moles = molarity x volume
so
M x V of HCl = 2 x M x V of Ca(OH)2
0.024 x 35.45 = 2 x M x 25
M = 0.017016
so
the concentration of Ca(OH)2 is 0.017016 M
3)
now
Ca(OH)2 ----> Ca+2 + 2 OH-
given
saturated concentration is 0.014 M
so
[Ca+2] = 0.014
[OH-] = 2 x 0.014 = 0.028
now
Ksp = [Ca+2] [OH-]^2
Ksp = [0.014] [0.028]^2
Ksp = 1.0976 x 10-5
so
the value of Ksp is 1.0976 x 10-5
4)
from wikipedia of calcium hydroxide , Ksp = 5.5 x 10-6