Formic acid act as reducing agent. Prove this statement.

Explanation

(i) Formic acid contains both an aldehyde as well as an acid group. Hence, like other aldehydes, formic acid can easily be oxidised and therefore acts as a strong reducing agent.

(ii) Formic acid reduces Tollen.s reagent ( ammonical silver nitrate solution ) to metallic silver .
`HCOO^(-) + underset("(Tollen.s reagent)")(2Ag^(+)) + 3OH^(-) to underset("Silver mirror")(2Ag) + CO_(3)^(2-) + 2H_2O`
(ii) Formic acid reduces Fehling.s solution . It reduces blue coloured cupric ions to red coloured cuprous ions .
`HCOO^(-) + underset("(Fehling solution) ( Blue)")(2Cu^(2+))+5OH^(-) to underset("Red precipitate")(Cu_2O darr) + CO_(3)^(2-) + 3H_2O`