H2O+F2→HF+HOF
oxidation number of F in F2=0
oxidation number of F in HF=−1
oxidation number of F in HOF=+1
Here,we see oxidation number ofFedecreases from zero to−1(HF) and increase from +1(HOF). This shows thatF2is both reduced as well as oxidised. hence, it is a redox reaction and more specifically , it is a disproportionation redox reaction.