Question

Phosphorus forms a number of oxoacids. Out of these oxoacids phosphinic acid has strong reducing property. Write its structure and also write a reaction showing its reducing behaviour.

Answer 1

Structure of phosphinic acid (Hypophosphorous acid) is as follows:

\[\begin{array}{cc}
\ce{O}\\
\phantom{}||\\
\underset{/\phantom{....}|\phantom{....}\backslash}{\ce{P}}\\
\phantom{..}\ce{H}\phantom{...}\ce{H}\phantom{..}\ce{OH}\phantom{.}
\end{array}\]

Reducing behaviour of phosphinic acid is observable in the reaction with silver nitrate given below:

\[\ce{4AgNO3 + 2H2O + H3PO2 -> 4Ag + 4HNO3 + H3PO4}\]