Oxygen is more electronegative than chlorine , therefore dispersal of negative charge present on chlorine increases from `ClO^(-)` to `ClO_(4)^(-)` ion because number of oxygen atoms attached to chlorine is increasing . Therefore, stability of ions will increase in the order given below
`ClO^(-)ltClO_(2)^(-)ltClO_(3)^(-)ltClO_(4)^(-)`
Due to increase in stability of conjugate base, acidic strength of corresponding acid increases in the same order
`HClOltHClO_(2)ltHClO_(3)ltHClO_(4)`
