C mol/L的Na2SO3溶液的质量平衡式是( )。
A. [SO32-]=C
B. [ Na+]=C
C. [ Na+]=3C
D. [SO32-]+[HSO3-]+[H2SO3]=C
已知H3PO4的pKa1=2.12.pKa2=7.20.pKa3=12.36,当溶液的pH为6.0时,则其各型体浓度的关系为:
A. [H3PO4]>[ H2PO4-]>[ HPO42-]
B. [ HPO42-]>[ PO43-]>[ H2PO4-]
C. [ HPO42-]>[ H2PO4-]>[ PO43-]
D. [ H2PO4-]>[ HPO42-]>[ H3PO4]
NaOH标准溶液滴定H3PO4至甲基红终点时的质子条件式是
A. [H+] + [H3PO4] = [OH-]+ [HPO42-] + [PO43-]
B. [H+] + [H3PO4] = [OH-] + [HPO42-] + 2[PO43-]
C. [H+] + 2[H3PO4] + [H2PO4-] = [OH-] + [PO43-]
D. [H+] + [Na+] = [OH-] + [H2PO4-] + 2[HPO42-] + 3[PO43-]