Question

What is the disproportionation reaction of `H_3PO_3`?

Answer 1

`4H_3` `PO_3` ----------> `3H_3` `PO_4` + `PH_3`

Explanation:

Disproportionation is a type of redox reaction where an element from a reaction undergoes both oxidation and reduction to form two different types of products. Similarly in case of `H_3` `PO_3` gives two products on diproportionation on heating.

On heating `H_3` `PO_3` it undergoes disproportionation reaction to give ortho phosphoric acid and phosphine.
`4H_3` `PO_3` ----------> `3H_3` `PO_4` + `PH_3`

Each element undergoes oxidation and reduction:

Oxidation half reaction =
`H_3` `PO_3` ----------> `H_3` `PO_4`

Reduction half reaction
`H_3` `PO_3` ----------> `PH_3`