among the oxoacids of halogens,their oxidation states exhibited by them are +1 ,+3,+5,+7 :

• Fluorine usually shows a negative oxidation state of -1 except in HOF where it shows an oxidation state of +1.
• The other halogens in addition to a negative oxidation state of -1 and positive oxidation state of +1 also show higher positive oxidation states of +3, +5 and +7.
• In principle, F should not show positive oxidation states since it is the most electronegative element known.
• In spite of this, F shows an oxidation state of +1 in highly stable HOF molecule.