For $\mathrm{H}_{3} \mathrm{PO}_{3}$ and $\mathrm{H}_{3} \mathrm{PO}_{4}$, the correct choice is

Question

Aicharya · Accepted Answer

The structure of $\mathrm{H}_{3} \mathrm{PO}_{3}$ is as given below.

There are only two-OH groups and hence it is dibasic. The oxidation number of $\mathrm{P}$ in this acid is $+3$, whereas $\mathrm{P}$ may have $+5$ oxidation state also. Therefore, $\mathrm{H}_{3} \mathrm{PO}_{3}$ can be oxidised which means $\mathrm{H}_{3} \mathrm{PO}_{3}$ is a reducing agent.

For $\mathrm{H}_{3} \mathrm{PO}_{3}$ and $\mathrm{H}_{3} \mathrm{PO}_{4}$, the correct choice is

Solution