Question

An experiment was performed to determine the Ksp of Ca(OH)2. Asolution containing 2.00 x 10^-2M Ca(NO3)2 was saturated withCa(OH)2 and filtered. Two samples of the saturated solution weretitrathed with 5.021 x 10^-2M HCl, in order to determine the OH-ion concentration in the saturated solution.

In doing this problem, note that 1 mol of HCl reacts with 1 molof OH- ions. This realtionship is the basis for the determinationof the OH- ion concentration: 1 mol Ca2+ ions are produced forevery 2 moles of OH- ions produced.

The data resulting from this experiment are shown below:

student data used to determine the Ksp of Ca(OH)2

determination

1 2

Volume of saturated Ca(OH)2 solution titrated, ml 52.2 48.7

Volume of 5.021 x 10^-2M HCl required, ml 16.44 15.49

Temperature of saturated solution, C 20.4 20.4

Calculate the following for determination 1 and 2:

1. Number of moles of H- ions titrated, mol

2.[OH-]sat.sol'n

3. [Ca2+] initial

4.[Ca2+] from dissolved Ca(OH)2

5.[Ca2+]sat.sol'n

6.Ksp