Which of the following acids forms three series of salts?

Options

A. `H_(3)PO_(2)`
B. `H_(3)BO_(3)`
C. `H_(3)PO_(4)`
D. `H_(3)PO_(3)`

Answer

C

Explanation

Structure of `H_(3)PO_(4)` is

`H_(3)PO_(4)` has `3-OH` groups i.e., has three ionisable H- atoms and hence forms three series of salts. These three possible series of salts for `H_(3)PO_(4)` are as follows
`NaH_(2)PO_(4),Na_(2)HPO_(4)and Na_(3)PO_(4)`