( I ) F₂ shows disproportionation reactions

( II )  F₂ is the weakest oxidising agent and it is always reduced.    

Disproportionation is a specific type of redox reaction in which a species is simultaneously reduced and oxidized to form two different products.
As fluorine shows an oxidation of only  -1 and has a tendency to reduce, it doesn't undergo disproportionation reaction.

Fluorine gas is the strongest oxidizing agent because of these factors:-

1. Very high electron gain enthalpy
2. Low bond dissociation enthalpy
3. Highest electronegativity and small size
4. Small size