Question

Orthophosphoric acid `(H_(3)PO_(4))` is not a reducing agent wheres hypophosphorus acid `(H_(3)PO_(2))` is a strong reducing agent "Explain and justify the above statement with the help of a suitable example.

Answer 1

The structure of `H_(3)PO_(2)` has two P-H bonds. Due to the presence of these P-H bonds, `H_(3)PO_(2)` act as a strong reducing agent.

Example `4AgNO_(3)+H_(3)PO_(2)+2H_(2)Oto 4Ag+H_(3)PO_(4)+4HNO_(3)`
Whereas `H_(3)PO_(4)` has all `P-OH.` Hence due to the absence of P-H bonds, it is not a reducing agent.