In aqueous solution, the acid $\ce{HIO}$ disproportionates according to the following equation where m, n, p and q are simple whole numbers in their lowest ratios.
$$\ce{mHIO → nI2 + pHIO3 + qH2O}$$
This equation can be balanced using oxidation numbers.
In $\ce{HIO}$ and $\ce{HIO3}$, the oxidation state of iodine is +1 and +5 respectively. Therefore in $\ce{HIO}$, iodine lost 4 electrons to iodine atoms, therefore n is 2 and finally p is 1. However, when the electrons are received by the iodine atoms, they should form iodide ions instead of molecules. How would you tackle this question?