1. A buffer system contains 0.18 MNH4+ and 0.14 M NH3. pKa of NH4+ is 9.25. How many moles of NaOH must be added to 1.00 L of this solution to increase the pH to 9.25?
2. Titration of a 15.0 mL solution of KOH requires 17.0 mL of 0.0250 M H2SO4 solution. What is the molarity of the KOH solution?
3. A 0.22 M solution of HCl is used to titrate 35.0 mL of a Ca(OH)2 solution of unknown concentration. If 140 mL of HCl is required, what is the concentration (in molarity) of the Ca(OH)2 solution?