1. When an acid, HA, is titrated with 0.1 M NaOH, the pH at the half equivalence point of the titration is 4.5. What is the Ka of the acid?
2. Calculate the concentration of calcium ions present in a saturated calcium phosphate solution. [Ksp Ca3(PO4)2 = 1.3 x 10-26]
3. Calculate the pH at the equivalence point for the titration of 0.20 M aniline (C6H5NH2, Kb = 3.8 x 10-10) with 0.20 M HCl. [Hint: remember the dilution factor caused by addition of titrant to the aniline solution.]