Explain why fluorine forms only one oxoacid, HOF.

Explanation

Chlorine, bromine and iodine form four types of oxoacids having general formula HOX, HOXO, `HOXO_(2)` and `HOXO_(3)` , in which the oxidation states of the halogens (X = Cl, Br or I) are + 1, +3, +5 and + 7, respectively. But fluorine forms only one oxoacid (HOF), at a very low temperature, in which the oxidation state of `F_(2)` is + 1.
`overset(0)(F_(2))+H_(2)O"(ice)"overset(233K)hArrHOoverset(+1)F+Hoverset(-1)F`
However, F cannot show higher oxidation states ( +3, +5 or + 7) due to the absence of d -orbitals. Hence, F does not form higher oxoacids such as HOFO, `HOFO_(2)` and `HOFO_(3)` , with +3, +5 and + 7 states, respectively.