已知H 2 C 2 O 4 是二元弱酸,酸式盐NaHC 2 O 4 的溶液呈酸性。30℃时,浓度均为0.1mol?L - 1 NaHC 2 O 4 溶液和Na 2 C 2 O 4 溶液中均存在的关系是
A.
c (H + )? c (OH - ) =1×10 - 14
B.
c (H + ) + c (H 2 C 2 O 4 ) = c (C 2 O 4 2- )+ c (OH - )
C.
c (Na + )+ c (H + )= c (OH - )+ c (HC 2 O 4 - - )+ 2 c (C 2 O 4 2 - )
D.
c (OH - ) = c (H + ) + c (HC 2 O 4 - )+ 2 c (H 2 C 2 O 4 )