Three reactions involving H_2PO_4^- are given | vedclass

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(A) An acid is a substance that donates a proton $(H^{+})$.In reaction $(i)$,$H_2PO_4^-$ is formed as a product,so it is not acting as an acid.In reac

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$(ii)$ only

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(A) An acid is a substance that donates a proton $(H^{+})$.In reaction $(i)$,$H_2PO_4^-$ is formed as a product,so it is not acting as an acid.In reaction $(ii)$,$H_2PO_4^- + H_2O \rightarrow HPO_4^{2-} + H_3O^{+}$,$H_2PO_4^-$ donates a proton to $H_2O$,thus it acts as an acid.In reaction $(iii)$,$H_2PO_4^- + OH^{-} \rightarrow H_2O + HPO_4^{2-}$,$H_2PO_4^-$ donates a proton to $OH^{-}$,thus it also acts as an acid.Therefore,$H_2PO_4^-$ acts as an acid in both $(ii)$ and $(iii)$.

Three reactions involving $H_2PO_4^-$ are given below :
$(i) \; H_3PO_4 + H_2O \rightarrow H_3O^{+} + H_2PO_4^-$
$(ii) \; H_2PO_4^- + H_2O \rightarrow HPO_4^{2-} + H_3O^{+}$
$(iii) \; H_2PO_4^- + OH^{-} \rightarrow H_2O + HPO_4^{2-}$
In which of the above does $H_2PO_4^-$ act as an acid?

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Three reactions involving $H_2PO_4^-$ are given below :$(i) \; H_3PO_4 + H_2O \rightarrow H_3O^{+} + H_2PO_4^-$$(ii) \; H_2PO_4^- + H_2O \rightarrow HPO_4^{2-} + H_3O^{+}$$(iii) \; H_2PO_4^- + OH^{-} \rightarrow H_2O + HPO_4^{2-}$In which of the above does $H_2PO_4^-$ act as an acid?