Q. Three reactions involving $H_{2}PO_{4}^{-}$ are given below (i)$H_{3}PO_{4} + H_{2}O \rightarrow H_{3}O^{+} + H_{2}PO_{4}^{-}$ (ii)$H_{2}PO_{4}^{-} + H_{2}O \rightarrow HPO_{4}^{2 -} + H_{3}O^{+}\$ (iii)$H_{2}PO_{4}^{-} + OH^{-} \rightarrow H_{3}PO_{4} + O^{2 -}$ In which of the above does $H_{2}PO_{4}^{-}$ act as an acid?
A) (ii) only
B) (i)and (ii)
C) (iii) only
D) (i) only
Explanation
(a)
Only in reaction (ii)$\ H_{2}PO_{4}^{-}$, gives $H^{+}to\ H_{2}O$, thus behaves as an acid.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.