H_(3)PO_(2)andH_(3)PO_(3) act as good reducing agents but H_(3)PO_(4) does not. Explain.

H_(3)PO_(2)andH_(3)PO_(3) act as good reducing agents but H_(3)PO_(4)

1.	H_(3)PO_(2)andH_(3)PO_(3) act as good reducing agents but H_(3)PO_(4) does not. Explain.
Answer» Solution :The STRUCTURE of these xooacids depends upon the number of P-H bonds. Since `H_(3)PO_(2)` has two, `H_(3)PO_(3)` has one THEREFORE, both ACT as reducing agents. In CONTRAST `H_(3)PO_(4)` does not have any P-H bonds and hence it does not act as a reducing AGENT.