下列溶液中有关判断正确的是( ) A.常温下pH = 2的HA溶液与pH = 12的MOH溶液任意比混合: C (H+) + c (M+) =" c" (OH-) + c (A-) B.pH相等的CH3COONa、 NaOH和Na2CO3三种溶液: C (NaOH) < c (CH3COONa) < c (Na2CO3) C.物质的量浓度相等的CH3COOH和CH3COONa溶液等体积混合: C (CH3COO-) + 2c (OH-) =" 2c" (H+) + c (CH3COOH) D. 0.1 mol / L的NaHA溶液,其pH = 4:c (HA-) > c (H+) > c (H2A) > c (A2-)