1. Calculate the pOH of a solution that results from mixing 30 mL of 0.11 M HBrO(aq) with 22 mL of 0.14 M NaBrO(aq). The K_a value for HBrO is 2 x 10^-9.

2. What is the buffer component ratio, (CH₃CH₂COO^-)/(CH₃CH₂COOH) of a propanoate buffer that has a pH of 5.05. K_a of CH₃CH₂COOH is 1.3 x 10^-5.

3. A buffer that contains 0.15 M of an acid, HA and 0.38 M of its conjugate base A^-, has a pH of 4.82. What is the pH after 0.036 mol of HCl are added to 0.72 L of the solution?

4. Calculate the pH during the titration of 36 mL of 0.22 M HBr with 0.15 M KOH after 11 mL of the base have been added.