Benzoic acid (CaHscO.H) has a Ka of 6.3 x 10-5. The most acidic proton in this compound is underlined in the chemical formula. A solution is prepared by mixing 85.0 mL of 0.162 M C.HSCO:H with 115.0 ml of 0.138 M sodium benzoate (CaHsCO2Na). Note that the benzoate anion is the conjugate base of benzoic acid. Assume that the volumes are additive. (a) (2 pts) Calculate the pH of this solution. (b) (3 pts) Suppose that 2.5 mmol of solid NaOH is added to the solution described in part (a). Calculate the new pH. Assume that the volume of the solution does not change as a result of the addition of the solid.