if we go through in inorganic compounds central element with highest oxidation state is maximum acidic in nature for example HClO4 >HClO3>HClO2>HClO,other is HClO₄>H₂SO₄>HNO₃>HNO₂ ,SO₃>SO₂  ,N₂O₅>NO₂ and many but if oxidation state is same than give preferance to electronegativity for example HClO4>HBrO4>HIO4  ,HOF>HOCl>HOBr>HOI  ,IN SOME CASES ACIDIC STRENGTH ALSO DECIDED BY BOND LENGTH FACTOR For example HI>HBr>HCl>HF  ,H2Te>H2Se>H2S>H2O