We can calculate the pH range over which a particular acid and its conjugate base can be used to make an effective buffer. If a buffer solution is created by adding NaOH to a solution of benzoic acid, C6H5COOH. (pka = 4.20). What is effective buffer range for the solution? O 1-7 O 10.80 - 8.80 O 2.20-6.20 O 3.20 - 5.20 O 7-14