H<sub>3</sub>PO<sub>4</sub>的pK<sub>a1</sub>,pK<sub>a2</sub>,pK<sub>a3</sub>分别是2.12,7.20,12.40,当H<sub>3</sub>PO<sub>4</sub>溶液的pH=7.80时,溶液中的存在形式的浓度大小,正确的是()
A、[H2PO4-]>[HPO42-]
B、[HPO42-]>[H2PO4-]
C、[H2PO4-]<[HPO42-]
D、[PO43-]>[HPO42-]
A、[H2PO4-]>[HPO42-]
B、[HPO42-]>[H2PO4-]
C、[H2PO4-]<[HPO42-]
D、[PO43-]>[HPO42-]
A、CaCO<sub>3sub>+H<sub>3sub>PO<sub>4sub> B、Ca<sub>5sub>F(PO<sub>4sub>)<sub>3sub>+H<sub>2sub>SO<sub>4sub> C、CaF<sub>2sub>+H<sub>3sub>PO<sub>4sub> D、CaSO<sub>4sub>+H<sub>3sub>PO<sub>4sub>
A、H<sub>2sub>PO<sub>4sub> B、H<sub>2sub>PO<sub>3sub> C、H<sub>3sub>PO<sub>4sub> D、HPO<sub>3sub>
A、H<sub>3sub>PO<sub>4sub> B、H<sub>3sub>PO<sub>3sub> C、H<sub>3sub>PO<sub>2sub> D、H<sub>4sub>P<sub>2sub>O<sub>7sub> E、(HPO<sub>3sub>)n
A、H<sub>2sub>C<sub>2sub>O<sub>4sub> B、稀H<sub>2sub>SO<sub>4sub> C、H<sub>2sub>CO<sub>3sub> D、H<sub>3sub>PO<sub>4sub>
A、H<sub>3sub>PO<sub>4sub> B、H<sub>2sub>PO-<sub>4sub> C、HPO2-<sub>4sub> D、PO3-<sub>4sub>
A、H<sub>2sub>C<sub>2sub>O<sub>4sub> B、稀H<sub>2sub>SO<sub>4sub> C、Na<sub>2sub>CO<sub>3sub> D、H<sub>3sub>PO<sub>4sub>