以下表述中错误的是 ( )
A. H2O作为酸的共轭碱是OH-
B. H2O作为碱的共轭酸是H3O+
C. 因为HAc的酸性强,故HAc的碱性必弱
D. HAc的碱性弱,则H2Ac+的酸性强
在一定温度下,离子强度增大,弱酸的标准平衡常数KaӨ将 ( )
A. 增大
B. 减小
C. 无影响
D. 减小至一定程度后趋于稳定
pH = 7.00的H3AsO4溶液有关组分平衡浓度的关系应该是 ( )(已知 H3AsO4 pKa1 = 2.20, pKa2 = 7.00, pKa3 = 11.50)
A. [H3AsO4] = [H2AsO4-]
B. [H2AsO4-] = [HAsO42-]
C. [HAsO42-] >[H2AsO4-]
D. [H3AsO4] >[HAsO42-]
用NaOH溶液滴定H3PO4溶液至pH = 4.7时,溶液的简化质子条件为 ( )(H3PO4的pKa1~pKa3分别是2.12、7.20、12.36)
A. [H3PO4] = [H2PO4-]
B. [H2PO4-] = [HPO42-]
C. [H3PO4] = [HPO42-]
D. [H3PO4] = 2[PO43-]