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` .