1: If 2.00 mL of a 0.40 M NaOH solution is added to 65.0 mL of a buffer solution that contains 0.10 M HCN and 0.10 M NaCN, calculate the change in pH of the solution (i.e. pH[after] - pH[before] ). For HCN, Ka = 4.9 e-10.
A. 1.1
B. 0.11
C. -0.22
D. -0.11
E. 0.38
2: If 20.0 mL of 0.15 M benzoic acid (a monoprotic acid) is titrated with 30.0 mL of 0.10 M NaOH, calculate the pH of the solution at the equivalence point. For benzoic acid, Ka = 6.3e-5.
A. 5.54
B. 2.53
C. 11.3
D. 8.49
E. 7.06