Orthophosphoric acid is tribasic and is not a reducing agent. Explain.

Explanation

Orthophosphoric acid `(H_3PO_4)` is tribasic, because it contains three OH groups attached to the phosphorus atom where all the hydrogens are replaceable. Hence, it is a tribasic acid.

It forms three series salt, by successive replacement of H atom of the .OH. group.
i.e, `H_3PO_4 iff H^(+) + H_2PO_4^(-)`
`H_2PO_(4)^(-) iff H^(+) + HPO_(4)^(-2)`
`HPO_(4)^(-) iff H^(+) + PO_(4)^(-3) `
These salts are known as dihydrogen phosphate, hydrogen phosphate and phosphate respectively. It is not a reducing agent because it does not contain a P - H bond.