The following acids have been arranged in the order of decreasing acid strength. Identify the correct order

$\text{ (I) }\mathrm{ClOH}\text{ (II) }\mathrm{BrOH}\text{ (III) }\mathrm{IOH}$

The oxidation state of halogens is same i.e. +1. Therefore the acidic character depends only upon the electronegativity. Higher the electronegativity of the halogen more easily it will pull the electrons of $\mathrm{O}-\mathrm{H}$ bond toward itself and hence, stronger is the acid.