A solution containing 0.0138M maleic acid and 0.0188M disodium maleate. The Ka​ values for maleic acid are 1.20×10 −2 (for K a1 ) and 5.37×10 −7 (for K a2 ). Calculate the pH of the solution.
A. pH = 2.12
B. pH = 4.78
C. pH = 7.00
D. pH = 9.36