How many milliliters of 0.12M HCN solution are required to be added to 56.0 mL of 0.21 M NaCN solution to produce a mixture of pH = 9.4 (Ka = 5.5 x10-10) = a. 65.0 mL b. 83.0 mL C. 42.2 mL d. 71.0 mL e. 52.0 mL